Well, it may happen... I wont be surprised if Aquarion returns in Z3.2 just so it can get combo attacks with the Evol version. So Diebuster and Gunbuster happening would be awesome as well.
After all they're gonna try and top @3 as that was their last trilogy series + Gaiden.
Splitting Z3 into two parts better mean we get an epic roster for the final confrontation with Ba-al!
And they better give Esther her darn Mecha Upgrade! You don't leave plot points like that untouched!
I also want them to continue Esther and Setsuko's relationship where Esther saw Setsuko as a big sister figure that she really respected and looked up to!