And yet, the Wii U version supports 37 different controllers.
Well the Wii U version is the main game that seems to be getting the most attention. If the leak screen shot of the select screen is the final stage count, the 3DS version has less stages then Brawl did and several series just reuse their Melee or Brawl stages without getting anything new. Despite the fact all of these franchises, Donkey Kong, Star Fox, Sonic, Wario and Metriod have handheld games Sakurai could have easily made a stage from.
Plus it's looking pretty likely at this point the 3DS version won't have a Event mode or Stage Builder either. If those are in the Wii U version along with the other modes except Smash Run which was said to be 3DS exclusive, the 3DS version is looking to be pretty half-assed in the end.
I wouldn't be surprised if this is why they really wanted the 3DS version to come first and why we haven't heard of the Wii U versions modes yet. After the Wii U version is fully revealed, the 3DS is going to look like a scam in comparison.