I know this isn't the end-all of power discussions, but the
Victorious Nation Sticky shows Pythium to tie for first in MA at two wins, and tie for second overall behind Caelum. I think you don't see them often because they only exist in MA, the least popular age. They're also doing quite well in the game that I'm playing (Casual PBEM).
The "old age has killed my nation!!" argument doesn't hold in my opinion; I've lost my share of sages and Lore Masters with a Death 3 domain, but it doesn't stop me from using them.