I've thought about if they should attempt at a Disgaea 1 & 2 compilation on Switch, seeing as both were PS2 games, and 2-packs of HD PS2 ports happened before on other systems (like Yakuza 1 & 2 HD on PS3 and Wii U).
I think a Disgaea 3 & 4 2-pack would be a large undertaking, if only because those are much more recent and are both PS3 games (hey if SE can do that with Dragon Quest Heroes 1 & 2 on Switch, why not).
A large candidate is Witch and the Hundred Knight 2... maybe, apparently that's out on PS4 next month? But that's on Sony's Phyre Engine, but I read that OlliOlli2 ran on it and that's on XBO so it's not just limited to SOny hardware (and mobile as a lot of its games are on apparently).
There's also the question of where do Gust, Falcom, and Compile Heart/Idea Factory go from here? Falcom seem like the least likely, seeing how they wouldn't even bother self-publishing the outsourced 3DS port of Gurumin 3D (FlyHigh Works did instead in Japan), hell it was Mastiff who got that port off the ground.
At least Gust did Rorona 3DS, and Compile Heart did numerous DS and a couple of Wii games way back, and Idea Factory did do a single 3DS game.