I kinda agree with you and i kind of dont. First of all i enjoyed the first one more....maybe because its the first game in the series and everything is new for example the great environments, animations and action set pieces, and if you were me who played the first game about a million times the awesomeness of the game kinda wares off......and by the time the 2nd one came it, you become accustomed to the game and everything feels familiar rather than fresh.
Another point against the 2nd game is that it had way more hype...and alot of the game was shown in videos and trailers( they should not have shown the video they showed at e3!!!!! that was one of the best gaming moments and e3 robbed me of it!!!!by the time i played it i already knew how that whole level was gona play out ) whereas uncharted 1 i bought on a whim and every level surprised me.
But despite these points against the 2nd game i can stil see why most people belive it to be the better game and why it is the better game. The final boss battle i thought was kewl and the ending was even better. And u talk about DF being harder...i think it was more annoying than difficult whereas the 2nd one was just right and the stealth was kewl to.
Overall what im saying is that had i played U2 first i would have liked it more and it is definately the better game but i understand why you prefered DF as i did 2=)