What would be the universally best PvP character for AvA?

Templar Solar spells make fire damage -> good for vampires.

Bow does poison damage -> good for werewolfs.

Both work well for other classes too, and ranged is good in AvA.

Templar gets heals without restoration staff.

Then one more weapon slot for CC/debuff.

Flame and poison damage are universally better than rest.

Idea is to have about same amount of magicka and stamina, because classes have skills that defend about one or other, or even get immunity. Maybe a bit more magicka for healing. Ranged gives possibility to use brains for gaming, as you can see the situation better and can react accordingly.

For every reason that you give why one of anything is better than the other, I should be able to give reason why it is not. If that question can be answered with any certainty whatsoever, then the game is systematically imbalanced.

For every Templar you will get two Nightblades and for every two of them you get three Sorcerers. Then you have the Dragon Knights that boast a very impressive arsenal they stand behind.

Answer is: all of them. Really depends of the player not of the character.

Yep, this is pretty much it. OP, there is no 'best' character for PvP.