Well you could mini-stealth in Unchartered, thats how you could run up behind pirates and snap some necks, then hide again; BUT the enemies in Uncharted have Hawk vision, Mouse hearing, they don't miss a beat and when they see one of their own missing they go into alert mode, and spin around guns pointed. They WILL catch you if you try extended sneaking.
Nate already does a form of stealth as he has all the mechanics except a crouch walk or stomach crawl. They would have to significantly decrease enemy A.I ( which I don't want ) and set hot routes to enable that form of stealth for e.g in Splinter Cell or MGS.
Its not too far off. I would just like to crack necks as long as could before I'm caught and the cover mechanic shooting begins.
Still Uncharted 2 can be balanced. For e.g a Chapters layout = action sequence, platforming sequence, action and platforming sequence, platforming, cinematic.
Its just all down to pacing