Fu Manchu with magic rings is derivative of undistinguished pulp writing, and worse, ignores all the ugly racial implications that could torpedo the movie's entertainment value. The first Iron Man movie was alert, focused on blowback and taking responsibility and Stark's fellow prisoner. The third movie was perfunctory enough. Incorporating the comic book Mandarin would have just been dickish.
Minor changes for modern sensibilities would have been fine. What we got in the movie was nothing
even remotely close to the Mandarin. He didn't have to be "Fu Manchu," but at least being real
would have been nice. Ditto for having the rings. And, you know, just being a real, challenging, and interesting villain. Not a washed-up actor using a stupid voice. (Which, somehow, isn't insulting to the Middle East anywhere as badly as a Fu Manchu type would have been to China. I guess making fun of their stereotypes is okay since they're currently America's "enemy.")
It'd be like Batman facing the Joker... only to find out that the Joker is just a sticker on the back of some redneck's pick-up. Or Superman pited against Lex Luthor... who turns out to be nothing more than the letters that were on some chick's Scrabble slate.
But nevermind any of that. Jarvis also disagrees. So does the Extremis project. Neither of which needed -- in any way, shape or form -- to be changed for "movie going audiences." Yet changed they were. Even more absurdly, no one in the movie universe has shown even a mild interest in the super-advanced AI that is Jarvis. Which in insane considering his capabilities. Even the AI in the mechanical arm would be worth risking everything to get.
(Also, do yourself a favor and read back over what this subtopic is about before ranting on some more.)