Darkarna
Grandmaster
Good. Run Alchemy. Others would run Parrying to counter. The more Alchemy is used, the more common Parrying would be. With expl pots nullified by the shields, mages would either 1) start using other builds, or 2) not, and have a dead skill. I'm good with either.
'Build diversity' in mage PvP is minimal at best anyway. Parrying would add diversity to melee builds.
Of course, skills like Poisoning need to be buffed for mage PvP anyway. And, with stun being essential, players would either choose between stun/alch, stun/scribe or having healing in there. Options.
Beating a dead horse man.. Watch out for maggots..