3e's Prestige Classes, as originally conceived, seemed like a decent notion, but actually made no sense at all. They were supposed to be elite organisations in the campaign world for PCs to join. Problem is that you had to be 7th level or so before you could even consider joining such a group (and, indeed, only a tiny percentage of 7th level PCs could meet the entry requirements). The NPC demographics made it very clear that characters of the requisite levels were vanishingly rare. And yet, the setting was supposed to contain not just one entire organisation of such characters, but any number of them?
I'm not a big fano of this comment on Prestige Classes:
The interesting thing about this approach is that it casts prestige classes as a DM tool that helps bring a world to life by giving starting characters goals in the campaign.
I prefer Prestige Classes (or Paragon Paths) as player tools to bring the gameworld to life and invest their PCs in it.
If there is going to be prestige classes I don't want to spend too much game time questing for them.
1 or 2 sessions per character to gain a prestige class? That's boring and a waste of time for valuable story advancement...
Also, having to plan a campaign from level 1 to give your players their prestige classes is no change from each player having to plan their character's feats from level 1
(Yeah, I use prestige classes as power-ups for my character, and as extra customization optionsBut the main objective is still the development of the campaign story we're telling)
I'm not a big fano of this comment on Prestige Classes:The interesting thing about this approach is that it casts prestige classes as a DM tool that helps bring a world to life by giving starting characters goals in the campaign.
I prefer Prestige Classes (or Paragon Paths) as player tools to bring the gameworld to life and invest their PCs in it.
And if players only care about PCs/PPs from the point of view of power-ups, that is not going to change by putting the GM in charge of handing them out. It will just mean that some players will jump through the GMs story-hoops in order to get the power up.
You can make prestige classes work. You should remove all but the most basic mechanical requirements, focusing on story-based requirements instead. Benefits of PrCs should also be less specific to individual classes, focusing instead on general usable features, indeed that needn't be mechanical at all, that complement rather than enhance a character. Allow only one prestige class per character. I would also remove them from the multiclass-level system - grant benefits on the basis of character level, not on the basis of how many levels you invest in the PrC, so that you can't optimise how many levels to take, nor when to start taking the PrC.
And with this, Next has jumped the shark. Prestige classes were one aspect of 3.x that should have stayed buried under several tons of concrete. Whatever the intended implementation, prestige classes will get out of control soon after release.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.