Seeing the gameplay trailer of MK1 I can only wonder how the hell they'll put it on Switch. A whole other build using some MK11 assets? Pre-rendered backgrounds?
Sonic tho looks really really impressive but it's actually quite feasible, we've seen some indies and 2D games just as impressive on the Switch, it's just that it's minimalistic and 2D style makes it mind blowing. I mean the NSMB aesthetic got everyone tired of it but the "models"(I remember seeing they went for a mid ground between sprites and modeling) were very rounded and everything was very clear.
I expect the 2D Mario game to rely heavily on 2.5D or something and be in the same ground as Dread, with Luigi's Mansion 3 being the dream but ain't happening imo.