There are certain champs, that go by untouched simply because they arent meta or a generally unpopular picks. This though, by no means makes them balanced in gameplay.
Champion that bothered me for a long time, that falls in that category is Zac.
Aside from amazing ganking presence, need to pretty much triple up your vision, and relentless pressure - his disruption and base dmg is plain idiotic.
Yes, other tanks have quality base dmg as well, but unlike Zac, they are mostly binary (Maokai,Malphite etc.), even tank Ekko is to some extend, easier to read.
This...slime is an issue because of his capability of constant pressence, which alows him to literaly throw around that base dmg constantly on everyone.
Furthermore, even if you actually manage to zero him out: 1. There are 4 guys with full hp left ready to blow you up, 2. there is his passive.
So i dont mind his ganking potential- its his trademark, but his general damage - especially in early, needs to drop.