The reason tribute bands were brought up was because for their summer concert series, they used to just bring in a bunch of tribute bands for popular bands. I don't disagree that it would fit Tomorrowland, but it's not there. Clearly Disney wants Epcot to be where the Marvel stuff is and whether it fits or not is almost irrelevant to the conversation due to that.
I understand your issue with it in WS, but if it has to be there, at least the show is good.