Hm, watching SRD's first hype video (he seems very hyped, and that makes me happy since he made so many cool plugins for MV), something that stuck with me is that he mentioned RPG Maker MV Trinity, the console releases.
In Trinity, there are a bunch of new features that are superior to the original "PC" MV we all here use. SRD said he assumes some of those features are very likely to be carried over to the next RM and I'd have to agree. Stuff like built-in foreground parallax as well the normal background parallax, right there in the engines map settings (unless my memory fails me).
I'd even go as far as making another prediction, which is that it's possible they'll take some of the expanded RTP made for trinity (they had voice actors and additional tilesets, large bust portraits etc) and put that in the next RM's RTP and just slightly add to it instead of making something entirely new. Because even if this is kinda sneaky, it would still be "fresh" content for the PC audience, and it would cost KADOKAWA nothing or very little to do this. I'd much prefer it if they just repackaged all that new content in a Trinity DLC pack but... you never know. They could do this... Maybe.
If that's what we're going to get though, I pray to the holy RM god that they at least decides to overhaul ALL character sprites (and add more) in the same style that they used for the free "Dark Fantasy DLC".
Those tall RTP sprites and SV battlers do look incredibly nice and if we got a complete set of those as well as a new character generator that could create such sprites... oh boy, then I'd be super happy. Even if they did port the Trinity RTP we'll still probably get at least a new sprite sheet of heroes since they need a new face that's not Harold's to represent the new RM anyway.
Even if that's all possible I still lean towards it's not being the case. They'll probably give us completely new RTP. UNLESS, this new engine is an "RPG MAKER MV Ace" or "RPG MAKER MV Pro", etc. If that's the case I'd say the above is very, very probable.
But yeah... well, speculations, speculations.
On a side note, I know you're reading this SRD (I'm a psychic!). I really hope you "come back" and remake your best plugin(s) if needed. That being the Super Tools Engine (and HUD maker). If not, I might throw an inter-dimensional banana peel your way... It could be super dangerous. Just sayin'.