I also share the same skepticism. Just to get something out of the way, it sounds like the DC issues are execution rather than anything wrong with the IP. So I am optimistic that can be fixed with the right person at the helm.
Anyway back to Nintendo, I have a feeling a lot of investors looking at Nintendo are looking at them through a very commercial lens, so their expectations are for them to follow the tried and tested models. As you mentioned, the MCU is a big success, so everyone should follow their strategy. If mobile is the next big thing, then everyone should start expanding to mobile.
However as
Matthew Ball has pointed out, Nintendo basically does things their way. It is very hard to know what they will do in the future.
So I am pessimistic about those views that hope for big profits from Nintendo going big into mobile/Nintendo Cinematic Universe or whatever others are doing. The only thing we can really expect them to do is to churn out
good game content and do weird things with their hardware.
It's not that they can't change, but their changes are held back/shaped by their company culture. I also do not know if it is wise to want them to, because they seem to have found a niche for themselves in a world of FPS games, brutal competition between PS and Xbox. Even the FTC complaint against the Activision Blizzard - Microsoft merger acknowledges that Nintendo is just in their weird category.
Sorry for the long post. Basically yes, let's not expect a NCU.
Back to the MCU, it does feel like it has peaked a little because the movies do not seem to generate the same excitement as before. I have a question though, what is a Cinematic Universe? It feels like this termed is used very loosely. Is it just a series of movies and/or shows that are tied together in one common/shared universe?
If so, it sounds like another tool that can be used to extract more $$$ from the IP, so maybe there is room for multiple CUs to exist. Maybe there isn't a need to beat Disney at their own game.