I'm going to be a realist here and give a resounding no. We've never received any of the other big name Final Fantasy staple spells (e.g. Flare, Flood, Holy) and I can't see why Square would change this now especially since it's Black Mages new toy. I find it much more likely that we would get AM or a similar spells before we got Comet.
Stopping to think about it I'm not sure how the dynamics of spell with a (potentially) gigantic casting time and huge spike damage would effect Puppetmaster. I've always been under the impression that large nukes were very much about timing (to avoid death) which we have very little tangible control over
Then again, on the other side, with our ability to remove all hate the and restore all our MP with deactivate we'd be erasing the real negatives of long casting time spells... which could be extremely overpowered.
I just can't see SE allowing Comet or any other similar spell any time soon. Feel free to disagree with me, I'd really like to be wrong here :)
Edited, Aug 22nd 2011 12:51pm by Mangotastic
.~* Anrete of Bahamut: Puppetmaster, Thief & Summoner *~.