last question, yes - except nowhere near as many enemies and nowhere near as frequently occurring as the set-pieces in RE4.
first bit - again, uncharted 2 is much more deliberately broken up between action,puzzles,platforming and story. combat/shooting dominates much more in RE4 over anything else than it does in uncharted 2.
unclear on the whole actually of what you mean by RE4 having more smaller skirmishes than UC2 because that.. just isnt true...at all.
the number of enemies per skirmish or set-piece in RE4 are ridiculously far greater than they are in UC2. i can think of countless consecutive skirmishes in RE4 where the area is flooded with far more enemies that what you will see on average in uncharted 2 - indeed, much of the game design of RE4 is to overwhelm the player with sheer numbers and from multiple directions. these types of encounters with comparable numbers of enemies are again far fewer and far between in uncharted 2, which yes, does make RE4 feel like a non-stop shooting gallery by comparison.
unless you mean the skirmishes in UC2 feel larger scale by virtue of the environment - sniping dudes from across two massive towers connected by a massive bridge - that is true.