Arcane is powerful stuff, but I don't think the form of Dispel Magic would affect its efficacy...I haven't read those rules in awhile, but I don't see how a BAR would apply to a Dispel Magic spell at all. Does the Bolt Form spell state such?
Re: Spell Typing, it's probably a touch overpowered as written. Just have your PC cast it once, though, an an opposing magic user with Spell Trigger setup ahead of time. If you allow multiple Spell Triggers, this can get especially nasty, and could explain why spell users are cautious around one another (i.e. everyone has nuclear weapons). "If spell cast on me involuntarily and I fail to resist, invoke Dispel Magic, invoke Fireball, invoke Teleport".