Someone tell me what's the logic behind removing omen slow and Frozen Mallet but not red buff slow

Because I don't get it.

Omen slow and Red buff slow both have no counterplay. One costed 3k gold. One is free. One slows and deals damage. One only slowed. The one that helped melees more was removed with no compensation. The one that helped ranged champions wasn't touched at all until multiple patches later (preseason 5) and still is going to exist unlike Omen slow.

Don't even get me started on Frozen Mallet. Massively nerfed in season 3, build path removed in season 3, now planning on being removed (according to Xypherous). Meanwhile ranged champions make any melee champion useless without any cost or cooldown except for the melee champions with no counterplay anyway like Maokai.

There's a reason why melee mobility creep is so damn high; the ones that aren't mobile get deleted from teamfights the instant a ranged AD gets a red buff, and are only useful as splitpushers. Then when those same champions have tools that can compete with red buff slow like targetted CC and gap closers people complain about THOSE but not about the nonexistent counterplay to red buff slow. You want to take a huge direction to fixing mobility creep? Remove the slow from red buff, at least on ranged autoattacks. Even removing it from melee champions is a good idea; it'll make CC tanks actually usable again instead of being outjungled by someone like Kha'Zix who only has 1 slow in his kit.