There are other recurring themes:
1. Twilight learns not to obsess.
2. Fluttershy learns to be less of a doormat.
3. Rainbow Dash learns something about herself. (It doesn't stick.)
4. AJ learns how important family is.
5. Rarity gets uglified and freaks out.
6. The End of the World is forestalled through the power of friendship.
7. Spike does something unforgivably stupid and is forgiven.
8. Gloaming Twinkle (or whatever GlimGlam's name is) learns not to fix problems by enchanting ponies into zombie robots.
9. Discord learns about friendship again.
I reckon there are others. Why single out Cutie Mark Confusion?