When we get direct feed screenshots of like-for-like scenes I will be interested in seeing what all the differences are.
Chances are KT didn't bother creating a bespoke version of the game for Switch that might sit in between PS3 and PS4, or be better than PS3 in some areas but worse in others, but they really did instead just take the Vita versions - whose file sizes are already adequate for a game card and models already scaled down - and did a quick and dirty port on it.
But it'll be hard to know for sure before we know about things like image quality, poly-count on characters and shadow map resolution as well as draw distance, LOD pop-in and so on. With heroes 1 at least we know that it looks like-for-like for PS3, but it's missing self-shadowing. Were the compromises on the Vita version that low?
The whole situation seems strange for sure.