wait… wat? So… MLP is a kid's show, but Steven Universe… isn't!?

Let me just try to ignore that comment

1. How do you exactly know who is stronger? When has it been established that Twilight is ABSOLUTELY stronger than Celestia? Also, doesn't it make since that someone with only a few followers would have to be very wise, strong, or powerful in some way to defeat an invading army on a global scale? Are the Pillar Men from JJBA Gary Stus? Zod and his followers? Bayonetta? Etc. Etc.
2. Most of the gems in the show are very colorful, and/or very uniquely designed hair styles, not just Rose.
3. How is being a significant leader/fighter to the enemy automatically Mary Sue?
4. They never shown that the villains hate Celestia… EVER!? Not Chrysalis when she made that speech to Celestia, Discord's coy yet obviously dislike of his punishment when he was freed, Tirek's pretty much hatred of all ponies, and Sombra's….. never mind, you get my point I hope.

They forgot Rose.