They don't call his moves "modified" because he botches them. All of Cena's moves are variation moves. That's how his character is, he makes everything his own. Takes what the normal is and changes it to better fit himself. They have never once called a botched move a "modified" move during Cena's matches. As for not being able to sell moves, that's just not true. At times he has problems selling the effects off a fight, but he always sells the moves themselves well. And, for a moveset, Cena added several moves over this past year. People complained about the "Five moves of death", and he added a few more. Then people keep complaining, even after he has a more diverse set. What you people fail to realize is that VINCE and the WWE staff has final say on peoples movesets. I.E. Cm Punk was forced to pick up an entirely different fighting style upon entering WWE. It's not Cena's fault if he's not allowed to do the moves he can do.
EDIT: A little more than a week with the title, and Orton has already botched an RKO, his SIGNATURE move, and hurt Jeff Hardy.
http://www.uowforums.com/showthread.php?t=112968
Orton just proved that he is already a worse champion than Cena...and, according to your prefering to have a WWE Champion that does not botch moves, once in a week is a bad start for him, so, unless your a hypocrit, you should be anti-Orton now.