Super Smash Brothers 4 is a bit of an odd game. It is currently out on the 3DS and is coming to the WiiU, but there are apparently going to be version differences. An example from the link above,
The 3DS version features an exclusive mode called Smash Run
The 3DS version also includes a StreetPass thing, which the WiiU is unlikely to have since it is not a handheld system that gets carried around in your pocket.
So far, the questions about the released 3DS version have been using the following tag:
super-smash-bros-4-3ds
If naming continues this way, then when the WiiU version releases, it should have this tag:
super-smash-bros-4-wiiu
There currently exists this question which is, at the moment, off topic because it discusses WiiU version functionality. It contains the tag:
super-smash-bros-4
I doubt we need 3 tags for a single game, so I think it should be discussed now, as 3DS version questions are coming in. This way, if the result is that we have a single tag for both versions, we can avoid having to do a wave of edits.