Hell yeah. I hope that they make it possible to have your character occasionally SIT DOWN! Even a hard-core gamer needs to be able to stop and to "smell the roses" from time-to-time, so-to-speak. The other thing that I hope that we'll be able to do is to use stealth techniques like some of what you get in the Hitman games -- such as being able to swipe disguises from unsuspecting guards, janitors, or kitchen personnel. Being able to non-lethally put down an enemy would be awesome too.
Finally, it would be great if you could complete many (if not all) missions with low body counts. I just like the challenge of completing a task while having to be careful about where (and who) you shoot. For instance, if you are careful and quiet enough, it would be great to make it easier to evade the police -- and possibly not even attract any police attention whatsoever. Plus, being able to hide bodies (alive or dead) would be a big plus.