I think there is room to debate the style of Hallowishes vs. Happily Ever After for superiority (although that's a bit surprising since I find Hallowishes to be a bit of a spiritual precursor to HEA with poppy versions of Disney hits giving a concert-like feel), but there is no question that HEA is TECHNOLOGICALLY-superior and a longer show. For most guests, that means "better". I think we can all understand someone paying an extra $500 for their family to go to an "exclusive" party wants to feel like they are unequivocally seeing better entertainment. That is true of the parade (which is objectively better than the nighttime parade guests see in the park on non-party nights.....................) and the Castle Forecourt show (plus entertainment elsewhere) but, apparently to many guests, not true of the fireworks.
I don't know why Celebrate the Season doesn't get similar complaints. Perhaps it's so saccharinely-sweetly-Christmas that no one dare complain? Plus the cricket. But once MNSSHP gets new fireworks, it won't take long for guests at the other party to expect a new show.
One consideration was (gag) HEA with a Halloween tag. I don't think they are going with that.