So going off League Of Legends boasting 100,000,000 active players (Item sets post)
http://www.riftherald.com/2016/9/13/12865314/monthly-lol-players-2016-active-worldwide
Riot said only 1% of players use the feature.
(intense math)
1% of 100,000,000 is 1,000,000
If they made improvements to item sets then it'd be well over 1%
But even if they didn't...
Is 1,000,000 people not enough to keep this feature for? Riot you say 1% like it's a small number but think about how much that actually is.
(That's more than a lot of games even have as active players)
It's clear this feature is wanted (And I bet you some people don't even know it exists).