This issue was brought up in the Sorcerer topic, but I wanted to talk about it some more. I really don't think the idea of PrC's for spellcasters is balanced. The reason being, spellcasters really don't sacrifice much of anything for taking a PrC that gives +1 caster level per PrC level.
Think about it. If a barbarian wants to take a PrC, he'll have to sacrifice some of his rage uses, some of his damage reduction, some of his uncanny dodge, and possibly his greater rage as well. A rogue who takes a PrC will be sacrificing some of his rogue special abilities and possibly some of his sneak attack damage. A fighter will be giving up a lot of extra feats. A monk who takes a PrC will be giving up his high level monk special abilities.
But if you're a cleric, and you take a PrC, and you get to keep your spell progression... What are you really giving up? Sure, you'll be less effective at turning undead, but that's not that big a deal. Same for wizards and sorcerers. If they get to keep their spells, they aren't really sacrificing anything to take a PrC.
This doesn't seem fair to me. Most of the non-spellcasting classes are making a tradeoff when they take a PrC. Sure, the abilities of the PrC will probably be better than the core class abilities they gave up, but they still had to sacrifice something. Spellcasters don't have to make that same choice, at least with many PrCs.
Opinions?
Think about it. If a barbarian wants to take a PrC, he'll have to sacrifice some of his rage uses, some of his damage reduction, some of his uncanny dodge, and possibly his greater rage as well. A rogue who takes a PrC will be sacrificing some of his rogue special abilities and possibly some of his sneak attack damage. A fighter will be giving up a lot of extra feats. A monk who takes a PrC will be giving up his high level monk special abilities.
But if you're a cleric, and you take a PrC, and you get to keep your spell progression... What are you really giving up? Sure, you'll be less effective at turning undead, but that's not that big a deal. Same for wizards and sorcerers. If they get to keep their spells, they aren't really sacrificing anything to take a PrC.
This doesn't seem fair to me. Most of the non-spellcasting classes are making a tradeoff when they take a PrC. Sure, the abilities of the PrC will probably be better than the core class abilities they gave up, but they still had to sacrifice something. Spellcasters don't have to make that same choice, at least with many PrCs.
Opinions?