Are there really too many PoGAs getting dropped? As you pointed out in the general discussion thread, any increase in their prevalence is likely influenced by the greater number of monsters in the recent releases.
As for PoGAs generated in other ways:
Minotaur Maze - dangerous, potential for stat drains, PITA
Dwarven Mystic - 50% chance for one, much worse than alternate reward
Black Unicorn - alignment hit, corruptions, loss of corruption removal
Alchemy - uncommon skill, chances are the recipe will require rare/valuable potions
Doesn't really seem excessive; am I missing any?
I guess it is a bit odd that PoGA is more common than potion of stat, but increasing the drop rate for those to 500 would address this just as well ;-P