I'd go with the former.
Heimerdinger pre-rework, Evelynn pre-rework and current, pre-rework Sion, Yorick, and a few others that my brain gives too few fucks for to think about. The usual excuse being "they introduce a toxic playstyle, so we're nerfing them until a rework", which is just defeatist at best, and a horrible example of balance/design at worst.
Espeically pre-rework Eve. She sat in the gutter for the longest time, got her rework, and then was promptly nerfed straight to the ground because her new kit was apparently toxic to play against as well, which speaks volumes about either the balance team or the champion design team. One of them isn't capable of doing their job very well sometimes. And by sometimes I mean 'look at the patch notes and try not to swallow a fly with your mouth agape so often.' I don't hate Riot, but their balance team is... not the best, unfortunately.