Cast twice per cast? What does that even mean? Every cast takes a GCD, casting two spells still takes two GCDs. It's an unfortunately common misconception that the instant cast is the same as an off global cool down. "Throw out utility"? Addle? Or embolden? Or do you mean raise?
1 the whole caster role has access to. 2 is a 2 minute combat utility which, fair. 3 will bankrupt you so hard you might as well be dead if you abuse it (read, use more than once per minute).
Now as far as BLM damage vs RDM, yes, raise and embo are calculated in. BLM is the strongest caster / dps because it brings no damage utility while Red Mage does. BLM is generally considered less mobile too, but basically it's as mobile as it needs to be. Neither caster likes having to move without preparation.