reminder to the riot devs: champion self slows feel like shit to play with.
putting self slows into champion kits as a lever for balance and counterplay is something that started already a long time ago, when garen was supposed to get a 30% self slow on his spin for hitting enemy champions with the juggernaut update.
luckily back then we were able to convince riot repertoir to replace the mechanic with a generally reduced spin damage, and a higher value against isolated targets instead to give opponents the ability to play around lane minions.
recently this worrying trend has been resurfacing with the rammus mini update and urgots rework.
while putting self slows into champion kits might make sense from a balance perspective, please keep in mind that it is probably one of the worst possible mechanics to play with. when youre playing a champion with a self slow on one of his abilities, youre feeling like youre gimping yourself for doing what youre supposed to do.
so please keep in mind to use mechanics like this very sparingly in champion kits, if at all. in my personal opinion, there are usually alternative solutions to create counterplay, just like riot repertor managed to do with garens spin.