I think they should make it were you can hide bodies. maybe use a tactical knife and a diferent execution death from above takes too long maybe grab enemy by his head while hanging from pipe and snap his neck tell me what features you think would be cool?
Well they removed carrying bodies and the knife, they also removed inverted takedowns. Maybe I'm missing the point of this discussion, but it seems this may be the first in the series you have played?(just an observation)
Anyways, I'm sure they will add carrying bodies back. And most likely bring back the knife, inverted takedowns. Possibly hacking and picking locks. I doubt they will bring back throwing objects as distractions or tapping walls. Maybe they will introduce some new stealth elements, or bring back more than what I've listed.
And I think all that you listed are cool, and most of the other stuff from previous games as well.