I'm not entirely sure, but it seems like duelist attacks twice as fast as dragoon/magilancer and three or four times as fast as gunner/sorceress/mirage caster.
All else being equal, I think I'd rank damage output as:
Sorceress (way out in first)
Duelist/Dragoon (I'm not really sure)
Magilancer
Mirage Caster
Gunslinger (They seem to deal less base damage than the healing class, and attack at the same speed.)
It seems like the only thing stats are used for is increasing damage. There's no stat that reduces the damage your hero takes. The only stat that matters is the one your main attack uses, the rest have no effect.
Also, gunslingers are absolutely useless. Unless you're really underleveled and want to kill something big from across a lake.
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