It regenerates very quickly and does not really provide ANYTHING other than a bottleneck for healers and arcane mages.
Why is it useless? Wouldn’t it have been better for DPS caster spells to do massively increased damage but actually USE mana when casted?
Why is this mana philosophy the way it is? It is an infinite, inexhaustible resource that can not be drained or otherwise consumed to empower spells, it’s like a remnant that might as well be removed from most DPS classes and no one would notice it’s gone.