Go kill a conq..if you manage to kill him..(i mean decent conq in pvp)..Come back here and tell me you killed him...Veng-gen PoM is overpowered cause it gains the best priest revamp of 2012 and it was before already a good class.
Some reasons :
-> Decent vengeance tree : With only 40 to 45 feats points you can have many many good dps feats like Searing eye of mitra, Immortal Wrath or Purification of Mitra. This is so far the best tree among priests. So they can use general to strengten up other stats like armor/protection, self-heal or dps.
-> A good magical spell coefficient : so they don't have to stack magic damage to be efficient. Most of the most deadly/unkillable PoM doesn't play with much t4 gear or stay with pvp t2/t3 one and still doing 3K+ searing eye. Thoses who play with T4 gear can stack up defensive accessories like Death Ward+AoK ring and PvP necklace/cloak and still doing very good with their damage output.
-> CC's. AoE CC's, Aoe cc's that can stack (repulse+repudiate), Cc's with auto recharge (LtP) Instant CC's (LtP). MMh, did i mention Cc's ?
-> Innate stuff :
* Bubble. This is great advantage since other priests have to get their bubble in their end-tree feat, wasting points in crap feats for that and therefore can't get any general feat.
Oh, and you can feat it (in vengeance tree ofc) to make it instant or better cd.
* Armor of Faith. Toggle innate armor buff. If you stack enough protection (pvp armor/weapons, pve rings, AA, wisdom), you can forget it against sins or necros.
* Litany of protection. Not imba ofc but still innate free stuff they got with revamp (ok toses got uber innate lsparks with their owns, replacing Degradation of Set lolz)