Guys, is this build insane?

I would give him close def and special fighter might be better, but it's pretty scary.

you'd better off with fierce breath and astra at that point, and just try 1 shot everyone trying to touch you.

I'd swap to Bonfire or Draconic Aura over Moonbow, personally. All his attack boosting skills are for enemy phase, so that's when he's going to be killing. He'll be getting an extra charge from the enemy hit (because you don't have Vantage so you won't hit first) so you can run a 3-charge special and still proc them on your return hit. Bonfire would give you +17 extra damage, Draconic Aura would give you 20 extra damage.