I know, but honestly I don't see what other metal gear solid games could be after both Rising and Ground Zeroes. and you're right, who knows maybe the idea of 4 maybe in ZOE 3 with the "Ender Project" Orbital Frames being the bad guys, having personalities like Dolores or something. not silly like her, but you get what I'm saying right?
I kind of get what you're saying, though returning to Leo being the protagonist and pilot of Jehuty may not be particularly desirable, considering there's not much room for character development for either Leo or A.D.A., and the concept of inducing character development might be a little too complicated to bear, or otherwise repetitive to the storyline as a whole. If you're interested in that kind of plot though, you might want to check the original Mobile Suit Gundam series, which was a likely basis for the first Z.O.E.
I get what your saying, and I used to be a fan of the gundam series, thinking that they're the best mechs ever, but recently after seeing the abilities of orbital frames, I've become more biased of them than gundams.
In a way, Orbital Frames rationalized the teleporting weaponry that was normally taken for granted across sci-fi and mecha series, which makes things pretty cool not to mention versatile. The direction of the plot of the Gundam series, however, is quite interesting (though I doubt I'll ever be able to make time for the series).