I had thought of starting a similar thread but more centred on asking whether EA fatigue would set in amongst the players due to the lengthy development and total lack of communication from Larian. It's pretty evident that Larian didn't realise the scale of the project they took on (which I find a quite staggering admission) and hence the development is well beyond their initial projections. Anyway, to answer you questions:

1. Community interaction has seemingly led to some minor changes but there has been a resounding silence from Larian until they make their Panel from Hell announcements every few months. Larian have their own interpretation for the BG IP and D&D and they won't digress too far from its current state, that much seems clear to me. Personally I think the game will suffer for it in terms of longevity and trying to appeal to too broad an audience but that's just my opinion.

2. It won't differ a huge amount.

3.I wondered about this myself, whether people would tire with the notion of another year of development with no communication and relatively little added apart from the occasional new class.

4. I mean, EA is what it is. I don't think anything further than Act 1 was ever promised.