Well according to insiders, HEA was suppose to be the Epcot Forever for the MK. A new permanent show was suppose to replace it a couple years later or something but that got put on the back burner after the response to HEA. Then when push came to shove we got DE for the 50th.
It's kinda funny that both HEA and EF, meant as temporary shows for their respective parts that reused music from the past are both coming back in a couple months simultaneously.
I believe that there were mixed-to-negative responses to both nighttime spectaculars that debuted on WDW's 50th, and on lesser extent, the entire entertainment offerings of 50th.
At the Magic Kingdom, the original DE was received heavy negative criticism of it, most of that criticism simply because the show didn't celebrate the history of WDW, lack of Disney classics, or the founder that started it all, Walt and Roy Disney. The updated version have improved the reception, although it didn't enough to appease the guest due to fact that it showed more than 10 months late after its 50th and two months into 51st anniversary.
At EPCOT, i suspected that Harmonious received many of negative criticism, although not similar height as the original DE, due to nature that the nighttime spectacular featuring Disney IP didn't fit well into EPCOT, which actually celebrate the history of the world's heritage. That's why many EPCOT purists hate the show and want a nighttime show like Illuminations ROE back or a new show similar to ROE. Additionally, fireworks barge at World Showcase Lagoon distracted the aesthetic view of the Lagoon.
It will be interested to see how the entertainment offerings for Disney100 at Disneyland such as new fireworks, WOC: One, and a returning daytime parade? Whether the offerings be better, similar to the WDW 50th, or worse? Time will tell. And if Disney want its entertainment offerings of Disney100 succeed to attract a positive response from visitors and fans alike, they must ensure they learn from mistake what they received during WDW 50th and the mistake cannot be repeated twice.