However, I have a player who portrays a Gunderman and after looking at the Gunderland Pikeman Prestige Class it nailed his idea of the character he wanted to develop, rules wise. As the PrC is not unbalanced at all, I think both him and the game profited from having this precise PrC.
I also think the Professional PrC is, in some respects, a good option for making more "realistic" thieves; in fact, a Burglar is better done with this PrC as it doesn't get an outrageous sneak attack (more suited to an assasin IMHO).
Of course, PrC characters should be exceptions and I think the classbooks with the multiclass options are the way to go, as Hyboria's Fiercest and Finest have shown.