I wish they kept Celestia and Luna as the only alicorns. Cadence (who was orginally supposed to be a unicorn until Hasbro put the kiabosh on DHX) opened a Pandora's Box.
DHX makes the show, not Hasbro. Hasbro knows how to make toys, not dictate a media company. They should make their toys according to the show, not force the show to conform to toys.
In a franchise (any franchise), the show should dictate the merch, not the other way around.