>>9918373POP was hugely experimental. She-Ra and the Horde were developed by men for an elementary-age audience of both sexes. Straczynski claims that the Horde being the government and She-Ra joining a rebellion was an early decision made to avoid just creating "He-Man with boobs", but no Rebels seem to have been created on the Filmation side besides Madame Razz and the Twiggets. That was filled in with characters being created at Mattel, with Justine Dantzer creating Bow and a character who seems to have been developed into both Gimmer and Angella, as well as Catra and the physical design of She-Ra. Frosta, Castaspella and Double Trouble came later from other designers, and when you look at all 8 you can see they were unsure how much MotU-style gimmickry to incorporate while still appealing to girls.
In the end, the POP toys seem to have been successful at doubling sales to little girls who were already into MotU ($250 million/$60 million in 1985 vs surveys indicating 25% of MotU toys were bought for girls).
Plus it seems without She-Ra, MotU wouldn't have had its Horde toys. Even if you're a toy-only fan, the fact is Filmation was the driving force of MotU sales: sales were $38 million in its one pre-cartoon year, and Filmation was done with it after 130 episodes. She-Ra was the experimental next step. It's not like Mattel had their shit together to do a male-centric relaunch in 1985. You can see in the relevant chapters of the Dark Horse art book that they weren't quite sure what they were doing in 1987-8.