Over on Tenkar's Tavern Erik talks about the addition of roleplaying hindrances to classes to balance class powers. His observations and many of the comments are mostly negative on the idea. I strongly disagree his conclusion about Paladin example which is to ban them from his campaign.
Roleplaying hindrances work when they flow out of how the referee runs his campaign. Like the powers of the classes themselves there is rarely a problem if that how the setting actually works. Paladins are divine champions of good and make sense that they have power beyond that of ordinary fighters. However they also only make sense if they are truly servants of good, just as it only makes sense for a character to be a knight if he showed loyalty to a liege at some point.
If the referee doesn't care about religions and ethics in his campaign that when he shouldn't allow Paladins as characters. But if on the other hand the referee does enjoy this type of roleplaying then the problem will fix itself as the player will be dealing with the complication of being a Paladins.
The various roleplaying limitations in my Majestic Wilderlands races and classes are the result of year of playing through various camapaigns and finding what worked and didn't work. Not just what I am interested in but also what is fun and enjoyable for the players that play in my games. The roleplaying hindrances that survive are those complications that both I and the players enjoy dealing with.
Class balance is a illusion and a mirage that wastes the time of referees while running their campaigns. After 35 years of roleplaying I am convinced that the only time balence is needed when you are attempting to be fair during some type of organized play like a tournament or game store events. Otherwise powers and abilities should reflect the genre or campaign the referee is running.