First and foremost, this is not an attempt to belittle, degrade, or poke fun at anyone that has a mental or physical handicap...
Since Xavier has been handicapped for quite some time, it's been a sort of iconic image to see him in a wheel chair - and everyone is comfortable with that. However in these quick-fix times, it's a lot easier to have a super-duper healing factor, or a bit of assistance from a team mate that can mend your broken bones lickety split... But then where's the fun in that?
Personally, I'd like to see a character go through the pain of losing a limb (Bishop, that's a whole different story), or mobility in their legs, like our American troops have done for our freedom. As expected, it would add to the realism of the risks and dangers they face every day (every arc), and humanize them far more than the whimsicle and lackluster drama we've been stomaching in the last 10 years... (save Mike Carey's work).
So what do you think? Would it add more dynamics and realism to the books if one or more characters became handicapped, succumbed to a heriditary deficiency, cancer, mental illness, or unexpected physical/mental reaction to the powers they've wielded all these years?
BTW, I realize there ARE other characters out there that have or had handicaps, but I'm referring to the more popular characters... whoever you think they are.