They did improve the SP...constant interviews stating the MP didn't damage their SP development. They hired guys specifically for MP. Played Uncharted 2 SP? No.
Of course they are going to state this. Is this a surprise? Of course Uncharted 2 is, most probably, going to be better than Uncharted, again, Naughty Dog is one of the best companies out there, where is the surprise? I´m sorry if my point was not explained the right way (english is my third language, so bear with me ). I was trying to say that Uncharted 2 SP would be better if there would be no MP, not that Uncharted 2 SP was not improved (when comparing to Uncharted 1) because of the MP part in Uncharted 2.
Even if the MP part was done by a completely different team (from programming to QA), you seriously do not believe that the projects leads et al have the same amount of time for SP if Uncharted 2 has MP and has not?
Today reviews will very often say that it is a minus that game has no multiplayer, hence MP is getting more and more standard. Again, I am against this and any other black/white reasoning mentality. Especially, if it´s the same old DM, CTF, co-op story...
Will you ever be able to play Uncharted 2 single player like it would´ve been without MP being developed at al? No, so we can maybe agree to disagree...
And to end this posting, I also believe that while developing a MP part you can find things that will improve the single player experience. But as time + budget are the biggest constrains, I still believe developing a SP only game with the same budget and time (and of course team) will get a better product then developing SP+MP with the same budget, time and team.
Hope I have managed to explain my view in a better way and take it for what it´s worth (comment from an avid player since 1984 or something with no ties/experience in the gaming industry at all)...
Have a nice day
Cheers...