Did Celestia Really banish Luna?

[Koelath 445]

Well, she blames herself it seems to an extent, as the whole thing brings up bad thoughts to her, and she even says the summer sun celebration was a terrible reminder she had to banish her own sister. So i think she has at least some remorse for it.

 

"I have bad thoughts when I think of the time I had to banish my sister." isn't a sign of guilt, it's a sign of not being a sociopath.

 

And when Luna became corrupted, she lost power over her side of the elements. That's why the mane six can utilize their full power while Celestia couldn't. The elements were in a state of disharmony when Celestia had to use them. They aren't meant for a single user. That's also why Celestia had to wait one thousand years for someone who possessed the magical energy and potential necessary to restore them to full power.

[Zygen 6,066]

"I have bad thoughts when I think of the time I had to banish my sister." isn't a sign of guilt, it's a sign of not being a sociopath.

 

And when Luna became corrupted, she lost power over her side of the elements. That's why the mane six can utilize their full power while Celestia couldn't. The elements were in a state of disharmony when Celestia had to use them. They aren't meant for a single user. That's also why Celestia had to wait one thousand years for someone who possessed the magical energy and potential necessary to restore them to full power.

I suppose you have a good point there. 

 

And i quite like your theory on the elements being in a state of disharmony. Thats quite interesting, and i quite like it .