The Formula won't change

[Sinstrel]

All that's happening is the servers remain up for people to play, and repeatable events (e.g. annual/seasonal events) may continue to run..

I agree with you about the hyperbole about the game being in "maintenance mode" when it isn't actually. But I think a lot of that sentiment comes from Yoshi & Co sticking to the set formula so stubbornly that much of the new content being release feels very similar to old content. Similar to the degree that it feels like its just the same repeatable/annual events, thus the "maintenance mode" hyperbole.