This will be a large entry so bear with me. I've done a lot of thinking about this because if I'm to send a letter to someone who may choose to run with this, it needs to be a solid concept.
I've been a Fallout fan for years, and I recently did another playthrough of New Vegas. Still enjoyable, still stunned at how entertained I was, and still wanting more.
A lot of times, especially with the Fallout games, the developers like to let the lore tell the story about what happened later; the fallout of your decisions, so to speak. You'll hear about the Chosen One or the Lone Wanderer in future games no matter how sparse the rumors. In this regard Obsidian was very clever in opting only for hints at what had been occurring on the east coast since Fallout 3.
With the closing of New Vegas the story indeed felt complete... or at least so I thought. However, after some pondering and due consideration I have come to the conclusion that that is not a necessity. Both Obsidiean and Bethesda LOVE to experiment. Granted, Bethesda seems to have opted a bit more for universal acceptance of their work, with the advent of Skyrim and all the appeal to previously untapped markets of gamers who fancy other genres perhaps but not intentionally at the expense of their core consumers. Either way, the game was new, diverged a bit from it's origins, and it was still a wonderful experience.
We all know and hope that Bethesda continues to bring Obsidian into the fold. There's been a lot of suggestions and hopes from both sides of the fence that Betheda continue developing their East Coast dystopia while allowing Obsidian to further develope the West Coast so well established by past Fallout titles. It is a good balance, especially if the teams consult one another and play the titles/take notes regarding what occurred in their counterpart's games so that they can properly interweave the two with perhaps a few slight references and nods; acknowledging the shared universe.
With that said, perhaps Obsidean should consider a strange yet new direction that no Fallout has really taken before. Not something that establishes a pattern for future titles, but something that can really give themselves and their fans something new and intriguing to try: the "file transfer" or "contigent continuity" cencept.
Mass Effect utilized the idea quite well. The idea that your character would become something more, and that your previous decisions carried weight in future games. Bioware, however, were not the first to dream up this ingenious aspect of gaming. The Suffering, a 2004 survival-horror game, did the same. Although theirs was a more straightforward way of handling the idea, Midway/Surreal did something interesting for gaming by making decisions matter. The Suffering read your save game data and loaded the outcomes from one of three possibilities based on decisions made within the games like saving someone or killing them. Long before that, Psycho Mantis of Metal Gear Solid would comment on the type of person you are based on the information the game extracted from your memory card regarding which games you played. This idea is time-tested as being extremely satisfying to gamers because unlike the "ulitmate end" they experience with most games, there is a feeling of genuine accomplishment regarding everything you did. And despite its media, is that not what many video games strive for? A closer and closer reflection of the person wielding the controller or keyboard?
There are MANY ways to handle this, all of which would work with varying degrees of difficulty for the developer and any of which should be HIGHLY satisfying for consumers thus ensuring good sales figures for the game, though in all honesty, I can't think of a main-series Fallout that didn't sell well. I will lay out these ideas by number for organization.
1. The TRUE continuance. In this scenario, YOU ARE THE COURIER. You pick up where you left off, whether years later, or simply right after the battle at Hoover Dam.
Methods of character extraction - Since unlike Mass Effect, Obsidian likely did not plan on such a direct sequel and has such would not have "flagged" outcomes in the file beyond what can be read by the game itself for the ending, there would be two easy ways to handle this.
-First way: Release a patch for the original New Vegas that would both set markers for reputation outcomes and end came scenarios. Since the original gmae had you load a save prior to the completion of the battle at Hoover Dam after completing it, this way might be difficult but surely not impossible. I also know that the games use character-gen codes for appearence, so that would be an easy way to import the character design, though that's largely unimportant.
-Second way: A storied menu at the start of the game where a narrator tells about the story of the Courier and you determine the outcome of the decisions and reputations in the first game.
-Alternatively: Just request the outcome of New Vegas with regard to who holds control, excluding the various faction and town based outcomes. This way is a bit less substantial, but it would relieve a LOT of stress on Obsidean's part for developing a game given how many different outcomes there are for each settlement and faction especially when you include the outcomes of DLC like Old World Blues.
With this first way, it would be interesting to continue on with your character. Features could be added that allow you to make economical and militaristic decisions given you chose an independant Vegas in the first game like choosing how to manage New Vegas with regard to security which could increase or decrease monthly earnings. Letting everyone in would increase earnings but run a higher risk of raiders and the like trying to take New Vegas and scaring people away. Alternatively, letting too few factrions into New Vegas would result in a low income which would not only provide the player with less benefits but remove features of New Vegas if enough time passes since there is not enough money flowing in to fund them. Same thing could go for the casinos, you could decide to lower your cut or squeeze them, affecting how well they do and whether or not the club stays open.
This same feature could work with ANY of the four outcomes given Obsidian goes the route of letting your character take control. For example, Caesar or Colonel Moore could put the Courier in charge of managing Vegas. Same thing could go for House. In this way, the choice you made to align with a faction STILL allows Obsidian the leniency of pre-progamming the inevitability that your character runs New Vegas without comprimising the faction you chose. Gamers too often complain that they are not given a choice that results in diversity without realizing the enormity of programming a game that widely diverges based on decisions. To do this, it would likely take a developer far too many years to put the game out on the same console, let alone enough resources and funding that would likely outweigh the cost-benefit of even making the game in the first place.
As much as I understand the disappointment of ME3's ending, there is a large following of people that understand that EA put them on a timeline and budget, which was not their choice. Working with Bethesda would allow Obsidean some room to manuever since Bethesda technically owns Zenimax, meaning the developer runs their own producer, which is a HIUGE advantage that allows them time and funding to complete games as they see fit. This is why we saw a 5 year gap between Oblivion and Skyrim, and why we are seeing such a huge gap between Fallout 3 and Fallout 4. The rumors for Fallout 4 are only just NOW circulating, so that should give you an idea.
I feel this idea would be more fan-based than it would dev-based given how much time and effort it would take to complete such a game.
2. The comprimise. You are NOT the Courier. You exist in or around the Mojave Wasteland. You are a character relevant to the Courier's story. You now opertate in a Vegas controlled by the previous protagonist, and as such his/her decisions weigh on the setting and lifestyle you lead. There will be a lot less explanation on this one than the previous entry because I've covered a lot of possibilities with that one that can apply to this and the following one.
In this scenario, perhaps you are a character that does the Courier's bidding, or are trying to take him/her down. Or perhaps the Courier is an entity beyond what you can hope to work with. Either way, the decisions you made in New Vegas can still affect the landscape, the atmosphere, and many elements in the Mojave. Within this scenario, less choices need to be made regarding what you did in the previous game, and perhaps we could even have a voiced Courier where you choose at the beginning whether your Courier was male or female, and what faction they allied with.
3. The reasonable. In this instance, New Vegas is DLC. This game takes place in a nearby land, or at least near enough for your character to visit New Vegas. At the beginning of this DLC, you choose a few details regarding your previous character like who you sided with, whether the characer was male or female, etc. Obsidean could build an interesting plot for a DLC that involves the previous Courier and allows you to explore a new more fully developed New Vegas shaped by the decisions made in the previous game.
That ends the scenarios that I have been able to come up with. I'm sure there are more possibilites, but I believe I've given the most basic and probable ones.
Thing is, places like Kickstarter have managed to revive games like Wasteland, and even produce consoles like OUYA. If a site where you can donate money can do something like that, then you can imagine what fans can do when they ALREADY love a series that has solid funding. A series where fans can promise their interest and their intent to purchase. I don't know whether or not Bethesda plans to give Obsidian further chances to expand the franchise, but I can tell you a lot of people loved New Vegas and I'm quite sure many of you would be more than willing to shell out a few sheckles for something like this.
I will end with this, and am more than open to further propositions and comments. Just please, be eloquent. Gamers made Wasteland 2 happen, gamers made Bioware create the Extended Cut for Mass Effect 3. YOUR VOICES MATTER!
All I can hope for is that Obsidean listens to its fans. All I can hope for is that Bethesda does the same. Even if it never happens, the fact that the desire was acknowledged matters. I assume that Obsidean isn't working on a future Fallout because I assume that they would alternate with Bethesda, and since Bethesda has only recently begun its work on Fallout 4, it's a fair assumption. What does this mean? It means TIME. It means Obsidian has the time to propose the idea to Bethesda. It means they have the time to work on it with the new Creative engine, which I assume Bethesda will use, it means they have time to listen to fans, to develop the game, to hear our battlecries!
P.S. I can't go back to a Fallout that doesn't include gambling. I really can't. That's a simple fact. My friend and I were so engrossed in the atmosphere of it that we are ordering custom cards and poker chips that are factory distressed to look like cards and chips that appear in New Vegas. Both display the logo of The Tops Casino. We are even building a Blackjack table that matches ones seen in The Tops, and several of our friends have committed to weekly blackjack games. Nerdy? We don't think so. The environment in New Vegas was something else. The old world music combined with the decrepit casinos and the fun of gambling attracted us to something we'd otherwise not cared about beyond perhaps the occasional fantasy football league.