Universes Beyond has plenty of properties to reach out to which would fit - Witcher, Dark Souls, GOT, Zelda, etc. which would all do incredibly well. And LOTR / Final Fantasy are certainly fine fits, with Warhammer 40K mostly-fitting.
The issue is that I don't think the concept of UB was really... ever mapped out. One-offs like Walking Dead or Street Fighter or Transformers were borderline, but not that many cards. Doctor Who, and the oncoming Marvel, are way, way more out of step. Of course, to make them fit in more comfortably, we've got sets like OTJ and MKM to strongly impress to the playerbase that the barest pretense of giving a shit about Magic's IP has long since left the building.