In the pilot of FiM, after Nightmare Moon destroys the Elements of Harmony in their ancient forms, Ruby personally blasts away at her (since Super Crystal Ruby can damage Dark Dian who’s even tougher than Diana who survived an explosion big enough to be seen from space, Ruby’s magic blasts should work just fine on NM) before combining her own magic with the ReManeing Five’s to purify NM. Then Celestia is convinced to not have Ruby or the ReManeing Five rely on friendship-powered ancient artifacts that can be destroyed very easily and only work when all of them are together. Ruby also doesn’t have a cutie mark, so Evil Starlight equalizing her is out of the question. Ruby also never becomes useless.
 
Meanwhile, Twilight trains at a Jewel Land magic academy to properly use her magic and has Sapphie as a friend. Twilight’s and Sapphie’s friendship proves more stable than Twilight’s and the ReManeing Five’s. Since the Jewelpet universe has never heard of the likes of the EoH, Twilight can actually personally defeat things. Eventually, she also gets a temporary human form that powers up her magic instead of taking it away.