MLP S4 EP25 SPOILERS

wtf why does Discord, who only recently reformed, and even then still isn't 100% trustworthy, get the chance to defeat the evil old guy, and not Twilight, yk, the, element of magic, fucking alicorn, who has been training for years, who is one of the most trustworthy ponies, finished a spell, keeps saving equestria, etc.???????????? God, Celestia isn't right in the head. even Luna and Cadence were shocked. my god. "oh but Discord is more powerful!11!!!1!!!!" guess who got turned to stone. twice. also I have a feeling just The Mane 6 would be more powerful than Discord, even without the elements of harmony, let alone if we added Cadence (not Celestia or Luna though, I love them but they're kinda useless 90% of the time, but yk, if they decided to be helpful, sure, add them!!!)