User blog comment:Mich, Michele & Kuhla/Future Units Preview/@comment-27268294-20151227141330/@comment-86.141.92.133-20151227200721

Alim creates the units (excpet the global exclusives) so you would have to ask them about the possible 8*.

Personnaly I hope no 8* except perhaps for certain mock units, say the ishgria demons (not the batch the actual bosses you face in the campaign so Shusui and the rest of them), Karna Mastra or whoever the sky orb belonged to originally (personal hope don't read anything into it) if Alim were ever to chose to make them. So only for unique units that you would get after some pain in  the ass trial in order to keep some game balance and not create a whole new dimension to the game like after the adding of 7*.