Sparring.
I run SK and Defiler, typically.
In this particular instance, I was a SK with the shield mage spec. And somehow, with basically just spamming mana stars, my mana was gone while the templar still had over 95% of his left
Against a templar or even worse a cleric it won't matter much if you up holy bolt mana x10 times, we have a huge pool of MP and it can be more massive if we do stat translation for Spirit + Cash shop limit enhancer, additionally depending on the weapon and sockets a high GS healer can basically refill the whole HP bar on a critical(which for a cleric is very high).
What I mean by this:
1.) if any healer have time to cast heals on himself, you are doing it wrong and you are dead.
2.) if you wait for the healer to run out of mp, you are doing it wrong and you are dead.
3.) if you have lower GS, you are dead but this apply to most arenas and classes.
How to beat holy bolt?
Extremely easy.
1.) Check your combos, you don't need DMG CC but Stun/Trip/Silence/etc. CC then Dmg CC then Stun/Trip/Silence/etc. CC, etc. As long as the healer can't cast you are guaranteed to win.
As a side note: I know most DPS are meatheads that want spam skills do 1 billion DMG and then trash talk because they are so awesome but news flash, there is such a thing as casting interruption in AA, is not a myth, is not an urban legend, it does actually exist and if you pay attention to what casting classes are doing(require some experience at first) you can interrupt heals and other magic based CC from happening and if you do that, again, I'm not joking, is for real, you don't get damage, amazing right?
Most of my wins as a plate templar in official and as cleric here(sparring since my Ayanad set is not ready yet) if because the noob try to win spamming DMG CC's, lmao. but every once in a while a DR/Primeval, etc. comes that actually have more than 3 working neurons and mix the CC properly and against those I basically get wrecked and I mean wrecked as perma stuned/tripped in 2 fights I couldn't actually land 1 hit wrecked.
Again, you cannot win against a healer in arenas if you only spawn DMG CC, it doesn't matter if holy bolt is MP nerfed by 1x or 2x or even 10x, is not gonna happen, accept it and learn to use your skills, practice with other people, etc.
The days of spamming battlerage combos F1-F4 to kill a healer are gone people, stop whining and go practice because you are doing it wrong unless your class have absolute no skill CC that can interrupt casting.