I worry about the talk of new gameplay mechanics in terms of genre and the conversation system. With regards to genre, I hope it stays third person, I have nothing against those who prefer a first person game but there is plenty of them out there, from a personal point of view I would like it to stay as it was previously.
The conversation system, I feel Mass Effect has the best one out there, it shows how your character and the other characters engage in dialogue and actions. Dodgy facial capture and animations aside, I always liked how they were presented. In games like Fallout and others I felt it was a one way thing, you see the character speak to you but not your actions and emotions, in some games you choose something to say but you don't hear it or see them say it.
I'm excited and nervous for this game, it's my favourite IP, I want to see it improve but not sacrifice or bring a " ain't broke so don't fix it" situation into the mix.