A perception problem develops in the mass market, however. If a class rewards skillful play with higher performance, the difference between average user and skilled user is increasingly dichotomous. If top end performance is approximately the same, but one class makes it really easy to get top end performance and the other makes it really hard....
Games like WoW have had this problem. For example, at one point, playing a mage was very straightforward, but playing a warlock was complex. Most people playing a mage could do decent damage, and there weren't a lot of ways for skilled players to rise above. The best mage player was only a few percentage points away from very mediocre players. The warlock, on the other hand, did very poor damage for most players, but skilled players were amazing.
Was it fair, however, to require such a high level of skill to play a warlock to the same level of effectiveness as a trained monkey could do with a mage? On the other hand, was it fair to skilled mage players for them to have no way to stand out above middling ones? Once you're dealing with a large player base who communicate with each other via internet forums and the like, these will become a concern.