My two cents:
the damage and sdi caps in PvP are what makes builds like BOK mage the most optimal for PvP, but they will lag pvm builds because the same caps don’t exist.
a sampire can armor ignore a monster for 180+, but only 35 in PvP. a pure pvm mage will out damage a PvP mage against monsters because they stack as much sdi for pvm and PvP caps sdi.
Bok mage optimizes how many skill points can be fit into a template to reach the caps for PvP melee and spell damage. The result is a very versatile PvP build that can deal lots of PvP damage and heal
You can pvm as a bok mage but will underperform the prevailing pvm templates.
a sampire with proper gearing and prep can PvP but will lag actually PvP templates.
With skill and prep any template can do both, but the meta templates exist because they are the most optimal for that type of fighting.
it also doesn’t help that someone who pvms mostly wont be prepared to fight a player.
most times a group will raid a champ spawn and then bring a sampire in to finish the boss.
That said, It’s cool to try things outside the box and I like to see new things work.