Methinks not enuf people have truly played AV to see how almost brokenly strong it is for a religion. AV priests gain access to both divine AND summoning, in the fire/death/chaos line. With chaos 1 divine, they get to gain mad exp at a small hit to power (whoopie, I wouldn't want to attack with them anyway). They get access to ring or fire/pillar of fire, as well as summoning nightmares and wraiths. A one-stop-shopping unit, you don't even NEED to research summoning if you want, and just focus on inquisitors/high priests. The only real drawback is the lack of spell extension, which is big, but still. A small hoard of ritualists (say 4-5) can easily tear down cities, especially if you are playing as the arc/sum leaders. Endless summons = never having to worry about rebuilding your units, you just get them back next turn for free.
Granted, AV's biggest weakspot is the need for reagents. If you don't have it reasonably closeby, I wouldn't even bother going AV.
As far as temples go, the extra gold other temples get is nice, but I often just use prophets/great merchants to add gold to the city and keep my research at 100%. I've been in many a game where the person chasing AV ending up fairly quickly a whole tier ahead of everyone else due to research, and the result was a total sweeping victory.
Finally, Rosier is MUCH better then Valin, for the one significant difference between them: Valin is anti-DEMON, but Rosier is anti-DISCIPLE. There are far more instances where anti-disciple is useful then anti-demon. All priests are disciple units, but only a few civs/religions build demon units, and many are summons.
