According to some MotU lore "the" power sword ws split in two, with he-man getting one and skeletor getting one (similar to the star sword in filmation's blackstar series). Later on we get she-ra, with a power sword of her own. Now here's where the puzzle lies; Is she-ra's sword equal to the pre-split power sword? Was the power sword actually split into 3, he-mans, skeletor's, and she-ra's? Is sh-ra's sword equal to he-man's half of the power sword, meaning that if he got skeletor's half and combined them back again his would be twice as powerful as hers? .......?

One possibility is tat the original power swords did get recombined, then split again, so she-ra basically has skeletor's half of the sword, except for the fact that in the intro episode, she-ra's sword had apparently been hidden away in greyskull since the 2 were born, so there was no opportunity to split it off from he-man's after merging his with skeletor's.

You're trying to make sense of a combination of two distinct lores developed by different companies at different stages of the series lifetime. Though let's try anyway

Consider that She-Ra's sword already has several abilities which He-Man's doesn't. For instance, it includes this communicator crystal and it can be turned into a shield, a lasso etc.

Clearly, being a girl (girls being weak, as everybody knows), She-Ra has something to compensate!