The whole idea that MM+ is a failure or is in big trouble is ridiculous. Anyone familiar with such huge technology projects (as I happen to be, unfortunately) they never come in on time and always have cost overruns. AND this board is hardly a place to look to objectively evaluate its success! There seems to be plenty of people that love MM+ and magic bands. Also Uni is poaching SW not Disney.
But there is a much more interesting question here:
There is a constant assumption that a successful theme park company will build new innovative rides every few years.
I reject that idea. In fact the current trend among some theme parks to build and build and build every few years is probably unsustainable. And even if it is, it isn't desirable. It is only necessary if you have to improve your product.
Disney is smart. They cannot promise a new ride every few years. They already have 4 successful parks with high attendance.
The real job is to create a great experience that includes lots of fun things to do and only once in a great while are those things updated or changed. For proof, MK is the most successful theme park in the world and it doesn't add new rides every few years. Doesn't need to. It is great to begin with.
(BTW - on a side note, I think the mine train may be an awesome ride. A fun rollercoaster with the new idea of swinging cars AND it can be ridden by a wide range of ages.)
I live near Hershey park which has turned itself into a great coaster park in a limited space, but it has been adding new coasters every few years now for a while and two things have happened: One, it is out of space, two, everyone expects a new ride now.
Yes Disney needs something more at AK and changes at HS, but I think Fantasy Land is great and MK doesn't need a great deal more. I am not a coaster junky, although I love them, I am a park aficionado. I don't think Disney should get in a spitting contest with a new ride every few years - too expensive and they don't need to.
I know that thinking would infuriate many here who WANT, want, WANT new rides, but it isn't necessary nor is it good business sense. Nor do I as a Disney fan need it.
Let the rest fight it out trying to attract attention every year or two to increase their share. Disney doesn't need to. I am not saying Disney should sit back and pay no attention to what is going on or that they shouldn't build new attractions, I am saying that the vitriol visited upon them for not doing new rides now and every few years for the last X number of years is unwarranted.
Epcot could be updated, but I enjoy it right now. I love the Land, the Sea, Mission Space, Energy, Test Track, and all of World Showcase. So some things are closed. Big deal. I have a blast. I don't have to have something new. Would I like it? SURE! Will I get it eventually, yes. But I love Epcot now. And MK. As is.

And I am not mad at them.
Disney should (from a fan
and business perspective) take its time and do Pandora right, then do SW right, and then move on to Epcot... all in good time. While watching attendance numbers and other factors. In so doing, slowly and carefully, they will do fine and may even cause the other parks a great deal of trouble.