There are lots of ways to fuck it up that this only kind of hints at--like that weird 'isolate effect' disability people sometimes write, where the only character who is impacted at all is the one who gets disabled (which could hypothetically work if they were a loner, but that's seldom the character type it gets written about), or worse, the designated hero of the story, who is then horribly traumatized and hurt by the disabling of their good dear friend/lover/associate/random bystander/etc. Although that's more of a 'yank the emotions' problem again, there. (And if it's a female character that gets disabled to the angst of a male one, you've achieved Fridging via Disability, for extra failpoints! See also the previously mentioned Barbara Gordon.)
You'll also frequently bump into minor or side characters who are disabled until a major character gets seriously interested in them, or they become a bigger part of the plot, in which case TADA! The disability is magically cured! And any 'unpleasant' personality traits associated with the disability also instantly vanish, of course, while 'attractive' ones, like the noble ability to forge on in desperate circumstances*, are left intact.
* And here we have a whole 'nother topic of rant I've been meaning to do since 2005. Why the hell are we always presented either as tragic warnings or inspirational stories? Can't we just be people, for god's sake? I can count the depictions of that I've seen on one hand, and quite terrifyingly, Leslie Neilsen is involved.