Why is Aurelion Sol "stronger"

I have a weird thought about the lore that's been bothering me for the better part of the past few months. Why is Aurelion Sol considered a mid, but Bard is considered a support? Why aren't they both considered mids? Lore wise, bard is more powerful then Aurelion Sol, yet his stats are only slightly higher.

The lore states

"When the unknowable structure of the universe is threatened, Bard steers all existence away from utter annihilation."

along with the fact that people who study Bard for their entire lives, only know a "fleeting aspect of his true purpose."

The lore for Aurelion Sol is much more tame compared to the cosmic savior Bard. According to the lore in Aurelion Sol's page all he does is create "celestial wonders" in the "vast emptiness of the cosmos" and in riot's teasers, and lore Aurelion Sol managed to get captured and tricked into whats basically slavery.

This is where it bothers me, Bard is enigmatic and can (and has) saved ALL existence from annihilation, yet Aurelion Sol was thoroughly investigated before he was forced to serve mortal creature. So with that comparison alone, why is Bard not considered a mid and/or stronger than Aurelion Sol?

Let's simplify things a little bit to make it less long winded. Bard stops the universe from destroying itself, Aurelion Sol put stars and stuff in the universe and somehow ended up a slave.

(and lets not get started on Soraka who can hurt Aurelion Sol with her Q Starfall )

TL;DR

Dear Riot, buff Bard or change the lore :P