What I find funny about the Uncharted series so far; Is the 1st one was mocked for being unoriginal and other crap, Yet the second is hailed a landmark game which apparently does everything better than anyone else. Kinda hypocritical in my opinion.
Naughty Dog has been known for being [what people may call] "unoriginal", actually; it's just that any lesser developer would pale in comparison to the amount of talent and skill that ND implements into their games, since they're capable of shaping the ideas they took from other games into something so polished and fun to play that all you're really left with is respect for what they've done, rather than feeling like you're playing a ripoff of another great game that has been introduced into the mainstream video game media.
Concerning what the critics have said, though, I don't think I've even witnessed anyone majorly criticize Uncharted for being unoriginal, to be honest; most of the criticism stemmed from cover, graphical, and enemy wave issues, if I recall correctly, but it probably depends on who you're referring to. Also, the main reason UC2 is praised isn't because of its originality or innovation (leave it to the EAD to surprise us with something like that…those talented, professional bastards...) anyway, but rather, its immersive, cinematic experience and almost flawless pacing. But hey, whatever a person prefers or believes is respectively their right, and I shall not try to provoke that..