TSR's Super Smash Bros Thread|SWITCH HYPE TRAIN NOW BOARDING

[TomGuycott]

One of the problems with porting the 3DS stages to the WiiU is more or less an asset thing. A lot of the 3DS stages like Prism Tower and Spirit Train take assets from 3DS games, and they'll have to be basically redone in high definition if they want to make them look good in HD. Even the stages taken from Brawl had some upscaling, just look at Hyrule Temple in Smash WiiU.

That is the main reason I think (disappointly in my opinion) that the 3DS stages probably won't be converted. Basically every asset will have to be made from scratch. Granted, data like how fighters react to terrain is probably able to be transferred over, but making new HD models for all of that may be daunting.