One of the big problems with a topic like this is that it tends to devolve into a discussion about characters who have been written by a large number of writers, sometimes over 3 mediums (Written (comics, books), TV (Live action and Animated), and Movies in particular, with many including Video Games as well) which have different requirements of the audience and of the medium.
Comic audiences are quite used to characters being "Repowered" when a new writer takes over. "Phoenix is too powerful, and Jean Grey is dead! So... resurrect her without any memory of her time as Phoenix. BRILLIANT!" and we comic fans go with it because it's becoming an industry standard. Or when a new wrinkle is introduced into a character out of the blue. "Wolverine's claws... are ALL NATURAL! And the adamantium has been retarding his healing factor - now that he's lost his skeleton he can regenerate FASTER than ever!" Then things get retconned, ignored, poorly explained or otherwise changed when something else comes up. Not to mention simply ignored for dramatic effect; in Comic 103, Black Wolf can smell a child in terror three kilometers down river while Black Wolf is literally being soaked in whiskey. But in Comic 137, Dirtypool sneaks up on a fully sober, fully clean Black Wolf and Black Wolf can't smell Dirtypool because DRAMATIC LICENSE! BW should be able to smell DP sneaking up on him without much effort given what we know of his Powers, yet the new writer wants to make a dramatic fight scene between the two so he ignores the powers of BW for that scene. (or part of it) We still ***** about them and roll our eyes, but we're willing to suspend our disbelief much more often than other audiences.
TV audiences don't accept this nearly as much as comic audiences. You also have the problem of having to actually show the audience what's happening - when you have a live-action version of X-Men (Generation X) you can't have a character doing the same things as they do in the comics - there's limits to our technology that stops us from showing the showier powers, and even those limits that can be gotten around can be more expensive than a TV show can afford. So you have to find a way to de-power the character for TV (and to a lesser extent, movies - bigger budget but still limited) so you have the comic character being more powerful than the Live-Action character.