I've been examining the APG. Very pleased with most of the content...except the Holy Vindicator.
It is too good. I feel it violates the principle that prestige classes should not be incredibly better than the base classes.
The mechanics of this principle can be implemented in the following ways:
1. The requirements of the PrC require tradeoffs
example: Arcane trickster requires 3 levels of rogue and 3 levels (minimum) of some arcane class
2. The class progression involves tradeoffs from the base class(es) used to qualify for it
Continuing example: Arcane trickster forgoes the capstone abilities of the arcane class and the additional rogue talents (including improved evasion)
I interpret the holy vinidcator as being designed for a paladin, but really being best taken by a cleric. There is little reason to continue in cleric past 8th level when a holy vindicator is available.
Comparison:
A paladin gives up:
additional Lay on Hands
Mercies
Divine Bond
Smite Evil
Aura powers
Holy Champion
They gain no new proficiencies, BAB or HD and lose 3 spellcasting levels (from a weak progression).
A cleric who waits to level 9 to start holy vindicator (so the 8th level domain power kicks in) gains the following (on top of PrC powers):
Better HD (d8 -> d10)
Better BAB (3/4 -> full)
Martial Weapon Proficiencies
Heavy Armor Proficiencies
And loses:
up to 3 levels of spellcasting
increased duration/power for some (but not all) domain powers
/Comparison
Channel Energy continues to stack with this PrC.
4 levels of Holy Vindicator means only a -1 caster level to spellcasting.
What cleric wouldn't dip into this PrC for the proficiencies and the HD/BAB (at least for 4 levels)?
Not having a cleric capstone makes divine spellcasting PrCs very difficult to design, because anything with decent caster progression is very tempting. I know this was dropped for a reason from the Beta (clerics too powerful with it?).
For my home games I will probably limit the PrC caster progression to an even level only (dropping from 7 levels to 5). This at least makes 20th level cleric/holy vindicators lose 9th level spells.
Please, Paizo, do not make the nice, well-thought out base classes obsolete! Keep the PrCs that require real tradeoffs.