Faith has a power thats good against any spellcaster. Temperance is ridiculous. Retribution, likewise. Depends on what you call deadly. I hit off 70 or so PKs with a sphere honor paladin who didn't give a crap about gear. I guarantee you if I was happy ganging people down with warriors I could've gotten many more than that. I stood for like 50 rounds in combat with 4 blades, one of which was the warmaster, thanks to temperance. They also couldn't lag me at all. Healers and shamans I could dispel and worldbind. Against other mages I still had the saves bonus.

I don't know. A serious PK'er with a paladin will do well. I'm honestly waiting for a paladin with 150 pks. If you're a gear whore and you gang there's no reason why thats an unviable number.