Well, I do think that Absorb is too cheap for what you get, whether you are Merc or Jedi.
If the flamethrower made your mishap meter fly up, which in turn made you vulnerable to force regardless of Absorb, I don't think it would be such a problem.
I really like the idea of guns making your mishap meter go up, and I think the same basic rules should apply: high mishap means force vulnerability, and mishap doesn't recharge while you're running. That would make it impossible to be a runner-gunner with huge weapons, and I'm in favor of that.