Again, I know that it is a phenomenon. But other franchises are also phenomenons, and a lot of them aren't even considered for Smash.
You explained exactly the imagery that comes to mind when thinking of Minecraft: Youtube culture
The game is popular among a lot of people, and I understand its importance. But I think that there are other series and characters that made a bigger impact, that stood against the test of time and are still relevant to this day.
I'm not necessarily against Steve in the game.
I'm more irked by Doom Guy and Ryu. People hyped Doom Guy for the same reason people hyped Bayonetta in the last generation: people were thirsting for new big third-party content that was more in line with the mainstream gaming culture that is predominant today, specially among the PS and Xbox crowds, regardless of their quality and coherence to what usually a Nintendo character is (I know this seems abstract, but I hope you get me). The fact that a franchise got to be ported just now doesn't mean it deserves the hype, if the series is not as "Nintendo" as say Megaman, FF, or even Minecraft. I know that my opinion isn't as popular, but I feel like the consistency of the roster should be maintained, and the game truly celebrates classic japanese gaming. Doom and Ninja Gaiden aren't series that come to mind when you think under these restrictions. Anyway, just my two cents.