Since I think NX is basically going to unify Nintendo's handheld and console ecosystem I think 10 million+ sales is actually underestimating the possible sales for a Splatoon sequel.
I think handheld owners would lap it up. Basically if you take the 3DS audience and let them buy Splatoon there's potential for a good 5X the sales of the Wii U version.
Splatoon managed about 4 million units on Wii U, even if NX is just a new console, that shifts 3X the Wii U's hardware sales, that's 12 million units of Splatoon (assuming sales scale linearly).
Opening up another 5X+ gamers Splatoon could easily top 20 million on NX, just because of the handheld owners being able to buy the game and the fact it's an established franchise now.
The potential for this game is huge IMO, I hope Nintendo iterates on the game's features, adding new cool ideas and pushes this game hard like they do with Mario titles.
I would have bought a Wii U by now, but because of the whole NX unknowns right now I've held off. I can even get one with MK8 and Splatoon for £219, which means the console only works out at like £160 for the 32GB model, but if NX is coming this year and the platform has backwards compatibility with Wii U then I'll just save up for the console or handheld version and buy Splatoon when I get NX.
IMO over 20 million is possible if NX unifies the handheld and console software libraries, if NX does standard Nintendo hardware numbers for a home console then I think 12 million is possible.
It just makes sense too me given the install bases of the combined Nintendo audience or even just the console market if NX is a standard home console, without having the unified library.
