Funny though isn't it that Patrick Stewart himself (by his own comments) DOESN'T see the project as a sequel to TNG - and WASN'T INTERESTED in doing such a sequel (which is why he told them 'no' many times before the final pitch that sold him).Just answering this one:
"Picard" is a very specific sequel, to a very specific character, played by a very specific character. Recurring elements from this character's history there is not "fanwank" or "needless fanservice". It's following up on core part of this very character's story.
If OTOH there was a new Trek show in the post-TNG time, on a fresh new starship, with new characters, and a fresh young actor as lead - THEN it would be "fanwank" if all they ever did was to introduce TNG/VOY/DS9-characters or elements or follow up plot-threads from there.
Apples to oranges. If they do a Pike-show - no one is going to complain that it will carry over recurring characters from DIS, like Pike, SPock, No. 1, Sarek or Empress L'Rell. Because they would belong there. But it would be fan-service if they then continue to introduce completely unrelated TOS elements like Horta, the Doomsday machine or the Gorn. Should be easy to understand, right?
Face it - because you LOVE TNG, you enjoy the fact that you're seeing other characters you love again. You don't care for the TOS era as much so you can't understand why fans who love that era were excited and interested they were bringing old characters those fans loved (and the writers and actors BOTH did an amazing job in bringing those new 21st century version of said characters to life - to the point fans of the TOS era WANT a 'Pike' show.)
So yeah, excuse me if I call out the fact that when it's something you don't care for it's degraded as 'fanwank'; but since TNG is are era you love anything there WRT bringing old characters back is just 'natural'/'logical'.
Again, Star Trek (TOS) has a 53 year history, and TNG has a 30 year history. I don't think it's either crazy, lazy or 'fanwank' for them to do things, like use or revist good/popular characters that give a nod to the older fans who've stuck with the franchise for years while still doing NEW stuff that does entice new fans to jump in.