I think the trick here is taking the game in new mechanical direction on the front of social interaction and exploration (particularly if they do anything like social combat or insert subsystems ike skill challenges), will further divide th base (at least if it is core). I think you and I have both been on some lengthy threads on this very subject, where it is pretty clear there are some strong divisions among gamers that could be described as "role play heavy" (and pbviously what that means was its own issue).
Yeah, well, as you probably know I think the "split" already exists; trying to pretend there are not radical differences between styles of play will really get us nowhere. I think folk are trying to cram more into "D&D" than any one game can hold; roleplaying is an activity with infinite scope - it's limited only by the imagination, which is not much of a limit at all - so, no game can encompass it all.
The last thing I want is mechanics that get in the way of me playing my guy (and to me this would be anything where social interactions are dealt with by a minigame such as social HP or anything more complicated than a diplomacy roll (and even then not 100% thrilled about that).
Right - this isn't really what I have in mind, any more than the combat rules dictate who your character fights or when they run away. What I have in mind is more along the lines of defining the social "terrain" - concepts like:
- establishing superiority or inferiority in a social milieu (where either can be useful - begging from a superior position seldom works)
- traditions and social rituals (entering the Duke's court can be worse than a beholder's lair; putting a foot wrong can earn you enemies you have never even met)
- plots are ways to multiply your influence or capabilities by clandestinely linking individuals (both PC and NPC) - each of whom is a potantial weak spot or traitor to the cause...
- beliefs and sentiments are palpable entities, sometimes, that can gain "currency" with whole swathes of folk in a social setting, such as a town or a kingdom. The feeling that "the orcs have a right to survive, the same as we do" becoming popular, especially among the leadership in a social group, can have marked consequences on half-orc bounty hunters in several ways...
- social "circles" form in every social setting; some of them rule, some of them plot, some of them seek influence. What are the "rules" for these entities? How does someone come to control one, and, through it, influence or control the wider setting?
There's huge scope here, I think, to develop ways of mapping and thus define the "field" on which social games play out. Exploration might be easier, but it brings its own challenges (mainly making it broad enough to cover a myriad of "inventions" in terms of hazards and challenges).
As a module this stuff culd work. Putting it into core might just lead to another split.
I'm not yet really convinced that "modules" can offer support for really different play styles. I think they'll be more like GURPS, where the genre and setting details can change as much as you like, but the core style of play is still recognisably GURPS (and none the worse for that!).