Nina has always been a top-tier - at least to me

Oh, okay so that is the change every Nina fan is moaning about, and quite frankly I also think it's an annoying change. That juggle ender saved me many times.

Anyway, I was just wondering: Which characters are considered top-tiers, mid-tiers, and low-tiers (if there are any). As a Tekken fan through many years I'm just curious.