You both describe my qualms regarding Metro -- these issues are what I'd like to see addressed in Last Light including the shooting; while not bad I agree with someone mentioning earlier about the the game being somewhat Bioshock-esque in that regard. None of these stop the game from being good, but taking them into account could make Last Light an amazing experience.
I would say tough enemies must remain tough. I hate it when I can play the game through without problems. I think it was possible to kill everyone in those 3 rooms. But I needed a little bit more luck and patience