I'm no great fan of The Mandarin in the comics, at all really. I didn't like the twist because it was poorly executed imo, and swapped out a mysterious, genuinely creepy and menacing villain, for a far less interesting or menacing one with poor motivations and who was basically just the same villain that we'd gotten in the other films (but with a different coat of paint).
Oh and it basically ignores the previous films almost completely (SHIELD was VERY interested in the Ten Rings in IM, and this guy is apparently their leader. And yet SHIELD is nowhere to be found here. Heck TONY never really brings up the fact that this guy is leading the group that held him captive for six months and killed Yinsen, nor does that seem to have any effect on him at all). I wonder if Shane Black even bothered to watch the first two films at all, or if he was just too concerned with being "cute and clever?"