Thats pretty messed up, unfortunately I feel as though the Switch will encounter a lot of issues with their ports. I know its not a port but I saw Xenoblade is running at a dynamic resolution that can drop to the 300P's I may pass on it because I know I will be pissed that the original wiiU version plays and looks much better. (30fps 720P)
The "Wii U version" is a totally different game (X vs. 2) and had its own set of limitations like more noticeable pop-in and no collision detection. Xenoblade 2 is a step up in visuals on the TV, it's just a little fugly at times on portable. Not at all unplayable.
In fact, I'm a PQ snob hoping for a patch but I'm still splitting my time with portable mode. On the TV, it occasionally will fool you that it's running at a higher resolution when it's not showing AA artifacts. In portable, it looks like an ambitious Vita game (which is underwhelming, but only ugly in the most taxing of situations).
To be honest, I'd rather they turned off the AA and sharpness filtering and just let the game run. I'd be okay with some steeped fps dips in portable, if the game set 480 or 540p as the low-end for dynamic resolution, rather than 360p.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."