It's not even the champs who could (or rather, should) benefit from a buff like this.
Diana's passive, Nasus' Q, Rengar's Q, Shen's passive, and Xin's Q are all great examples of this.
Every hero you listed has trouble pushing hard (with the exception of Rengar at 5 stacks and a late game Nasus). They all need something to help them push, since their kits don't otherwise provide it.
I don't see how these are ridiculous or unfair? All of these boost damage, reset AAs, etc.
Garens Q as well
Talons Q melts towers
Gosh I remember the first time I saw rengar, he was like level 4 and took down a tower in no time at all, thankfully he got a nerf but he still has that potential.
TF Blue Card!
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