Basically:
-A lot of the old stuff is still around
-However, most of these old things (mechanics, etc) will have different contexts, elaborations and extensions (armor, mako, etc)
This is IMO rather limiting on info for friggin 2015, but hopefully E3 will change, or at least start to change that.
What we're missing:
-What is the new stuff? (we only have rumors)
-How much is new? (from what we know so far, it'll actually try to be more new than old, at least compared to how ME2-ME3 were done, but we don't know details)
-How much, exactly, of the old stuff is around? (we know it'll be around, but will it matter or just be nostalgia bits?)
-What is the context of the new stuff? (the big thing, that may wait until the pre-launch leadup for the devs/marketing to get into with us, like usual with Bioware games)
The message I've seen so far about relating to the previous games is that choices will be recognized, but focus more on nods than a cause-effect of choices. This may mean a lot, a LOT of nods, and even characters/events that can be explained more by us playing previous games, but still, ultimately, nods. Maybe think closer to ME2's nods than ME3's effects, while still having a legacy of 3 games of choices to potentially 'nod' about.
(So think ME2 nods + ME3's number of effects = NME's number of nods lol)
Also, even if previous game choices may not impact a lot, it may still effect things, and the next game may instead try to focus on decisions WITHIN the game mattering more than ever before. Maybe. I just feel they've been pushing the concept of NME being like 'multiple ME trilogy games in one', and so with this could mean that it isn't about transferring between games, but instead having a more contained story, albeit maybe a big one with lots of decision effects as you go along.
In any case, I've seen nothing that would go the other way and deny that the trilogy's decisions will have nothing to do with the next game. The context may dramatically change, and the developer focus may not care nearly as much about providing specific big consequences to specific actions, but it does seem like the next game's story won't, in itself, ignore that the trilogy's events happened. We just need to be prepared for a relatively more stand-alone story and game though.
I'm ready for a DA Keep-ish system to be announced.