While I'll never actually touch it on the Switch (or PS4 more than likley, praise be native 4k support on PC), i'm looking forward to seeing the Switch version. SE have clearly had a lot of trouble with it, so it'll be interesting to see what it ends up looking like.
I expect the biggest issue they're having is that they know the Switch version will be very popular (particularly in Japan), so it needs to be a great port. Porting good looking PS4 titles down to the Switch is already difficult, but when they're 30fps and you want the port to be good, it becomes a real challenge. Significant asset reworking becomes a strict necessity, and looking at the fairly barebones graphics options on the PC version I'd guess a lot of those lower quality Switch assets are having to be made specifically for it. Combine this all with the engine difficulties they had (I believe they were using an older version of UE4 than the Switch supports? Correct me if I've miss-remembered that), and I can understand why it's taking a while to make a solid port. I expect it'll hold up well compared to the PS4 version, but it'll be fun to examine the specifics.
The game runs on a version of UE4 that doesn't support Switch. So in order for them to port it, they also have to make upgrades to the engine.