Where do Gameplay suggestions go?

Hello!

Recently, I compiled a topic involving a suggestion I developed for altering the in-game summoner spells and posted said topic in the "Gameplay" boards. As I have seen plenty of Suggestions placed here prior, I had assumed that it was the proper sub-forum. Not too long after, my topic was deleted, and I was recommended to repost my topic in Concepts & Creations, which I subsequently did.

However, I don't feel like Concepts & Creations is a proper board for my idea, as my idea is not an artistic, literary, or champion concept but rather a suggested idea to improve gameplay. This, on top of the fact there are already Suggestions in the Gameplay subforum, make me question what's really accepted in the Gameplay forum.

Can I get a Rioter to explain what the actual requirements are for a suggestion to be placed in the Gameplay subforum?