Which is pretty much nonsense. Anybody or anything "popular enough" can be an exception here. The writers may call in Spock or Section 31 or whatever, not being limited in the slightest by something being or not being TNG. They have no reason to be purist about this, no reason to assume any segment of the audience will prefer pure TNG over some mixture or another. And they have already demonstrated this clearly enough, by having Seven and the Abrams Armageddon of Romulus as key bits of their story.
Timo Saloniemi
Timo Saloniemi