I wonder, if Storybook Circus is the placeholder it seems to be (and I do hope it is, though I appreciate it in the short term) what that will mean for Dumbo if and when they go to make a change. I can't picture them wanting to get rid of it, even if the numbers are down since the move. If the Circus Tents went away there would not me bunch circus left to speak of in the area.
I think I wouldn't be too surprised if one day Barnstormer went the way of the Dodo in light of the Seven Dwarfs Mine Train (although much is left to be seen about how they affect each other) and was replaced by some other, smaller Circus representation, keeping the feel in the area to justify Dumbo's continued presence while allowing the northern area to be redeveloped.
It would be silly if they built, say, a Frozen ride where the tents are now, only to have Dumbo and Barnstormer sitting randomly across the way. I'd hope for them to take any new development in that area seriously, rather than just plopping something in.