looong comment
I would probably donate to a project started by Obsdian -- provided you give us more than what DoubleFine did (it's why I have not donated to them yet). I want a game concept, more than a genre and a promise that it will either be great or horrible. What is the setting, what elements do you want to try? The game can fail, in a sense, but we need to know more about what you want to create. We know we're taking a risk, but we need to be a little more informed about this risk. When a lot of the big picture is laid out, then I will support you.
What would I like to see? First of all, Obsidian does great work, but you guys also have made some big flops. You've not always had the best gameplay ideas, though your narrative and the general flow of the game tends to be incredible.
I would like to see a unique, unused setting. Perhaps something pre-historic and/or anachronistic. Maybe something political? The Indus valley civilization. The ancient Olmec, the forgotten people of Teotihuacan, the people of Ankor Wat. Something quietly sinister. Something unknown. Something mystical and ancient combined with modern elements (Perhaps the cities surrounding these great ruins are really anachronistic, with some modern inventions like guns or steel or machinery or very advanced mathematics or philosophy).
I would absolutely love to see "Kreia" return. As far as I'm concerned, she's the best character to have been featured in your games. A "neutral", unreliable yet wise character with a complex motive. If you can promise someone like Kreia, I will shell out sixty American dollars.
You don't need a large cast of party members. Three to four will suffice, if they're all of sufficient depth and design. The scope of the game does not need to be "epic"; though it should obviously be of some decent length (longer than the newest Final Fantasy we were just graced with, which clocks in at under 25 hours).
As for gameplay, you can do "traditional" Baldur's Gate-like combat with its isometric perspective. Or you could do something real-time like Skyrim (though please, please don't copy Skyrim's abominable combat system). I would only ask that spells and abilities be unique or at least interesting. Skyrim is exactly the antithesis of this, in terms of spells and abilities.
If you were to use the mesoamerican setting, you could easily do an interesting ability system using blood sacrifice (or some kind of sacrifice to the gods) or something different like that. Actually, green /obsidian/ was of immense importance to the central american cultures... it symbolizes rebirth. That could easily be your currency too...
A 'Planescape 2' is a bad direction to go in. But to call it that to get more donations? Go right ahead. Grim Fandango is an excellent example of how a creative 'morbid' setting can go. Planescape's right up there with it. Why I love Planescape so much is because of its setting... so getting the setting right is important.
I want female characters that matter. That just aren't pieces of ass like Tali or Miranda from Mass Effect. I like Visas, but I think you can create a strong female role which is more complex than hers. Of course, 'keep it simple stupid' is also not a bad strategy to undertake. For this kind of project, you're getting all the money up front (though I suppose you want to consider selling this on Steam or something afterwards too), so I expect there to be a little level-headedness. You can't go overboard with your freedom, as that, in my experience, tends to create a lesser product. Some self-constraint is good. Romance? Well, a little bit is fine, but female characters exist to capture that other 'essence' of humanity and sex hardly has to do with that.
Graphics don't matter. Voice acting does not matter. I don't want loads of money poured into either of these. In fact, you can have "average" graphics and that will more than suffice. Voice acting? It can be completely unvoiced. The only RPG which has ever had voice contribute to its atmosphere and value was Vampire Bloodlines: The Masquerade (though I guess some of Obsidian's Voice Acting has been good in the past). I doubt you will be able to achieve quality voice actors on a budget, so just skip this. A good soundtrack is great though. But just look at how bad voice acting detracts from the The Elder Scrolls games - don't do it!
I don't think I need to tell you how to write. You do a great job at it. You can write the game like it's meant to be followed up by a sequel or not. But please, please, please make choices matter. Mass Effect is such a disappointment. Don't be afraid to go all out with this. Plan from the very beginning to make choices matter thoughout the game. If I **** up and the world ends, great! What you decide in the first five minutes of the game should directly effect what happens halfway through it, if you can manage that!
The game being easily mod-able and open-world are big pluses but not required.
I hope you're not teasing us by asking this question. I think a lot of us are serious. We would pay you $60 or more if gauranteed us another jewel like KOTOR2 or Planescape.