The trailers look incredible, and I like free-roaming rooftop-climbing multiple-paths-to-objective style gameplay. However, nothing I've seen of it has sold the story to me, and that's a big make-or-break for me.
Also, Bethesda games have this long-standing policy of being grand and without peer in the big picture while failing in the small particulars. The difference being roaming throughout a city or landscape versus sitting down for a drink with your mate. The first parts they know better than anyone, but the latter is always stiff and soulless and unnatural. Not that this kept Skyrim from making a bajillion dollars, though.
Still, I'm at a point where I'm getting mature enough (read: pretentious enough) to not be interested if the non-action experience is too shallow. I'll wait for the reviews to come in on this one.