for me? the answer is OBVIOUSLY Starlight Glimmer, the pony whose tragic backstory is "failed communist dictator decides to unmake reality because she sees herself as fundamentally broken"
i support women's wrongs, and i love this twisted anti-twilight whose first thought when coming up against any friendship problem is just "oh i'll use magic to override peoples' wills, it works every time"
also she has a fantastic redemption arc! a much lesser show would have her do a face turn and then be Nice Now, but even after several seasons she's still a macchiavellian bitch who has emotional problems -- but she's learned to use those traits for good! she knows her weak points and her strengths, and does her best while remaining true to the person she was. she goes from a pony who abuses her authority, to a pony who's afraid of being in power (because she's scared she'll fall back into her old patterns), to a pony who's forced to step up and be a reliable authority figure. it's a really compelling character arc!!
also after years of friendship lessons she's still the most combat-ready bitch in the entire main cast. check this clip from the finale: a threat appears to the school, so she IMMEDIATELY gets it away from the kids, uses her enemy's power against her, and uses the environment to her advantage and decisive victory. the only reason she doesn't succeed is because chrysalis is hopped up on Magic Bell Powers
you just KNOW she stays up late fantasizing about battle plans to keep her students safe. this is NOT a spur-of-the-moment combat choice lmao
also she and trixie are lesbians supreme and i think that's Good
there is ONE best pony and it's the one that was written in as a weird anti-communist allegory but then turned out to be a huge badass instead
