The rest of your comment like you said is "not for you anymore". That's all personal taste. It seems that the general public and many here (including myself) really like this show with the main critique being that it is too short.
Now listening to this version of The Magic is Calling makes me wish that this was the main theme of Disney Enchantment. It's such a great song and already sounds like it could have been in a nighttime spectacular.
I understand what you state fully, but I just don't see it being a new building. Either way, Disney will confirm what will happen and fortunately we will be having new entertainment on Main Street U.S.A.
The easiest and most logical place to place a "Theater" on Main Street U.S.A. is in the current theater. What would be the point of having two structures named "theater" that look very similar on the exterior?
They said on Main Street U.S.A. at the Magic Kingdom. Looking at the building, it's obviously the theater. You can even see the backstage gates that they use when the park is crowded on the left in green.
Like I said, I wanted to state as you just said here, you find Disney Dreams Spectacular due to the water effects, but many find Happily Ever After spectacular the way it is. I originally wanted to point out in a separate post that each firework spectacular shouldn't have all the same effects as...
Don't forget that Disneyland Paris now has Disney Illuminations now which is basically a slightly watered down version of Ignite the Dream from Shanghai Disneyland. Also just to point out, the best nighttime show for you of coarse may not be the same for others.