With the exception of sales the same can be said about Rayman (who's been on far more platforms than Minecraft and also has Nintendo content), yet he's not playable either. How much of Minecraft's success is owed to it being on Nintendo? What necessitates it a playable character position in Smash Bros? A few trophies, a stage or an assist trophy is understandable. A playable character, not so much. Especially since Minecraft isn't a franchise known for character. Sakurai's already mentioned that standards for third party characters are much higher than first party ones.
How much of Final Fantasy 7's success is owed to being on Nintendo? Zero.
Snake has a history with Nintendo, but the MGS series is what's popular and what is exclusively used for Snake in Smash and none of that series success has anything to do with Nintendo, hell Snake's outfit is from a game that didn't even come to Nintendo.
Stop making up personal rules and making flimsy justifications for why you think characters don't deserve a spot, it should be clear at this point that all that matters is if they are a video game character and if Sakurai wants them. Minecraft has every right to have a playable rep, it just remains to be seen if Sakurai wants do do that.
Slimmer build, different hair.What's the difference between base Goku and uhhhh... vanilla Goku?