I love Soejima and all, but Kaneko's designs just ooze a quintessential SMT style. Particularly in Nocturne with all the minimalists designs.
His version of Dante's devil trigger was so unique and had so much personality.
I wonder if down the line, when Atlus mixes things up, what Kaneko's return to the Persona series would look like. Or maybe more interestingly, what a Catherine-like game would look like with his design sensibilities.
Alternately, a Soejima Devil Summoner could be interesting, especially if they set it a generation or two later than Raidou XIV.
In fact, fuggit. Just make a game devoted to the entire Kuzunoha line as a series of episode all fighting a mysterious demon slowly gaining power and "edit" it like Millennium Actress.