I have no problem with the series moving to Switch. The problem I have is that we've gotten 2/3rds of a trilogy on Vita and the third title exists for the platform, but we don't get to play it in English.
I love the Vita as much as anybody but the Atelier series switching to Switch is only a good thing in my mind. I picked up one of the earlier Vita ports (Totori I think?) and the performance & loads bothered me even back then - I've heard the sequels are even worse in that regard. A portable Atelier game without visual, performance, or load compromises is just what I would need to get back into the series.
Since it exists; is being translated and the previous games clearly sold well enough for them to keep coming, it would've been nice if we could've just gotten a quick stick-it-up-on-PSN for those of us who don't have a Switch and don't mind playing Atelier with visual; performance or load compromises (which, judging by Nights of Azure 2, is coming anyway to Switch because Gust can't optimize lol).
In other Koei-Tecmo news that shouldn't surprise anyone, Attack on Titan 2 also skipping Vita in the west:
Looks like Toukiden 2 will be the final Koei-Tecmo western Vita release. I suspect AoT2 will be the final Koei-Tecmo Vita release in general.