As long as we can't place objects in the game's areas, and script conversations and quests, modding will be confined to rebalancing and cosmetic changes to art. Conversation nodes can easily be edited, but there isn't much point to doing this, even if we weren't "blessed" with full VO.
However, even just modifying numbers can bring about very interesting rebalance mods. I have a lot of ideas about how to turn Deadfire into a great grognard experience, and other people will certainly have their ideas.
BTW, I also made a small UI mod for PoE: https://www.nexusmods.com/pillarsofeternity/mods/8
I'm looking for mods like adding voice lines like "Fus Roh Dah" for chanters, or change the spiritshifted form to the regular animal form (bear,cat,boar,etc.). Hating the weird model of the spiritshifting which looks more like werewolves. Also.. modding the 6th party characters in (however, Josh stated in some of the interviews stating this as impossible as most the UI being designed with just 5 party members instead of 6). I'm not really sure why they really discourage or intentionally disallow the 6th character in. Possibly it would be due to platform parity. As the games going to be released on multi-platform, many developers discourage mods so that the platforms do not have noticeable advantage over the others, in my opinion of course.
I personally like the 6th party character mod and i believe this will make many classic players happy. I don't see 6 characters as a balancing issue (if there's a enemy scaling mod). Also mods to change the circles to character highlights (this is already possible as characters were highlighted if they are being obstructed by buildings). I'm not sure how i would i can mod it myself but i would even go to the extend in paying for these mods if any good folks out there willing to do it.
Hello
You can do it. You must update the Assembly CSharp.dll
Look at iemod on github, patche your dll to make all class and methods public and édit PartyMemberAI (AddPartyMember method) and UIPortraitBar (awake method). You need visual studio and a little knowledge of C#.
Your game will crash un cutscene when your party is auto move to location (spawn point) (like then theater cutscene)
I have finish the game with 6 party member - but play with incremented difficulty for balance.
I think, i can post a full detailled tutorial for the parching part if someone need.