There is no shortage, in the online wrestling community, of discussion centered on which wrestlers have been under-utilised (and, generally, the same batch of names come up: Shelton Benjamin, Rob Van Dam, Matt Hardy).
But these aberrations can, in most cases, be - if not exactly forgiven - at least explained away by the fact that our internet darlings (as Triple H might refer to them as) shared the stage with better, or perhaps more marketable, wrestlers who were afforded the opportunities that may have otherwise been sent their way.
When it comes to the reverse - stars who are pushed beyond their actual level - it's a little more difficult to rationalise, since sport (which WWE is, kind of) is supposed to be a meritocracy, where the cream always rises to the top.
In practice, though, that just isn't always the case. You can make it to the top of wrestling simply by being in the right place in the right time, making friends with the right people, or simply possessing some arbitrary attribute (usually physical) that sets you apart from everyone else.