Who is the Best tank counter?

As someone who plays a decent amount of ranked (Legendary 2), for the last few months or since his hypers release, I maxed out gale, and almost only used him as my gkk on to CC or tank counter. After seeing SpenLC's recent videos, I found that gale just isn't getting the job done.

I am wondering who would be the best alternative to gale, as someone to stun, slow, knock back, etc, and counter those annoying tank picks.