That post MSQ talk with the Flame General was pretty heavy handed making sure to mention Ilberd and Ala Mhigo. I feel we will see him in 3.5 if I had to guess. Not 3.4, I feel that one will be sort of an epilogue to 3.x, 3.5 will be the prologue to 4.0, that's when the Ala Mhigo front will be front and center and lead itself to reentering Ilberg.

For my money with that mention and the fact that when he used what looked like an updated Red Lotus after using EnFire on his blade while fighting Raubahn, leads me to believe not only will he be back in 4.0 or before. I believe he will be involved in the Red Mage job quest, either as a quest giver or an enemy depending on if the character is redeemed or not.

I mean Red Mage-like skills in an expansion that has two named/hinted jobs, its obvious.