Hm... well the game is balanced around 4 PCs all around the same power level. If one PC gets too good at something, then this balance is thrown off, even if he or she isn't stepping on anyone else's toes. This only means the DM has to be proactive with what is allowed and what is disallowed. Usually these overpowered PrC combos are from different sourcebooks which the developers weren't considering interacting when they wrote them, thus the DM needs to step in and say no to PCs who want to use them.
Odhanan said:
What frustrates me often with PrCs are the prerequisites. Not that they are so bad, but the requirements often ask from a player to think on a metagame point of view, to specialize and sacrifice character development for the sake of the "right feats at the right time to get the PrC at this precise level". There are just too much mechanical requirements to PrCs, and not enough RP requirements (know members of the group, have a personality like this or like that) in my opinion.
That has been a concern of mine from the beginning when a PC first thought about taking a PrC. You cannot grow into PrC. The game makes it very difficult to actually introduce PrCs into a campaign through
play. To attain a PrC a PC pretty much has to know he's going for it at character creation. This makes it much more difficult to make them tied to organizations.
The PCs don't know that they're going to meet the Templars of Urd (or whatever) in their travels, so how, when one decides to join that order and gain the PrC, will that occur? "Oh no, you don't have the Tower Shield proficiency which is a requirement for this Prestige Class... oh and 7 ranks of Knowlege (Nobility and Leadership), that will take you 3 levels to get if you put every point in it... better start now."
No, they can't do that. So the Players don't look for interesting roleplaying PrCs, they look for ones that will help their "crunchyness." Ideas are what's important here. Deepwood Sniper is great! They know they want to be good with a bow, so the player looks at the requirements and when creating his character makes sure that he's going to be able to get it.
Bandits of the Gnarly Wood might be an even better fit with great roleplay potential to it and a great story for his joining up, but when a player makes their character they don't have any idea they'll be running into the Bandits of the Gnarly Wood and that they have a PrC that would fit him. The DM at this point probably doesn't even know, because through
play is usually where you find out where the story is going (unless you run a more linear gameplay and have players who are into that).
Thus, as specific organizations for players to join, the very nature of the Prestige Class is a difficult mold for that.