In what way?

Annie is a twisted little girl.

Teen Annie is an angsty, angry teenage girl who channels her emotions into her spells.

As a child, Annie was entirely oblivious to the amount of fear that people had for her.

Teen Annie has finally realized her own differences. She carries a teddy bear, everyone fears her. She can never have a true friend, besides Amumu.

The only thing is? She's also realized her own powers.

Doesn't like the idea of sexualizing a little girl.

No teen Annie because no one at Riot is interested in indulging your silly little sexual fantasy about an underage girl.

Maybe this might happen if Riot is ever taken over by Japanese overlords.

Last I checked, the issue was that the lore says teen Annie would be absurdly powerful.

Because it would create a lot of bull**** they don't feel like dealing with.

Seriously, turn off safesearch and check google image for "league of legends annie". You'll get "images" within the first 20 rows. Now tell yourself the amount of those will multiply by ten if they make that skin.