Finally put the lid on the first Uncharted on Normal mode. My capsule review: a solid, satisfying action-adventure game, part Tomb Raider (without the frustrating camera and awful checkpoint system) and part Gears of War. (Though not quite as varied in enemy and weaponry selection.) The graphics are a real stunner, even rivaling the best of today's console gaming, and both music and voice acting are terrifc. Some of the vehicle sections I could've done without, like the jet ski sections. But other than that, it's a great quest while it lasts.
Here are some things I'd love to see improved upon for the sequel:
Tone down the waves of enemies that are constantly bombarding you. I know it's the game's natural way of padding game time, but it didn't take me long to get battle fatigue after the third or fourth encounter in a row. Not only that, but they swarm you in such a way that survival, at least from the way I've been playing, means having to trek back to the farthest part of the beginning of an area to 'funnel' them toward you in a safe manner. I found myself having to rely on this tactic more and more as the game went on, rather than being able to utilize the immediate environments for effective cover.
As Wanderer stated, more enemy types would be great. Better variety in the weapons could also give you a better fighting chance against swarming enemies. Should they decide to keep the high encounter rate of battles the same (and for some reason, I think they inevitably will) this could go a long way toward alleviating the aforementioned problems. Also, more opportunities to use QTE combos for close quarters combat. They're great to look at, but don't come often enough -- and when they do, it can be difficult to pull 'em off right.
More boss battles. The few featured were quite cool, but like Gears 2, it'd be great to have more of them to punctuate the action.
Bring Greg Edmonson back for composing duties. The soundtrack to the first is a perfect mood-setting blend of the exotic and the exciting. Besides which, I just want to hear more works from the guy; anyone know if he's done anything else?
Some niggling gameplay and aesthetic fixes are in order. Make the grenades more effective to use, and further refine how Nate sticks to walls when taking cover. Fix up the screen-tearing issues, which, from what people are saying about the recently multiplayer beta, Naughty Dog has thankfully done.
What did you think of that wretched church battle near the very end? 
