We're probably going to see reasonable-ish winrates on it when the meta settles, but only because people will stop playing decks that rely on bronze synergies. I've had this concern in past metas, where scissors counters paper so hard that people only play scissors and rock and each has a 50% winrate. This time any decks built around key bronzes are going to disappear, and while these decks are gimmicky they're usually fun to make and pilot.
Examples include decks built around Brokilon Sentinel, Svalblood Priest, Gan Ceann, Cintrian Royal Guard, Vigilantes, Firesworn Scribe, Griffin Witcher Adept, and probably others I'm forgetting. You know, the meme decks this sub loves. Wagenburg for pure armor decks also qualifies though at least it's a more expensive target.
Additionally, Scoundrel devalues units as tech cards (ie Pellar) because it can get rid of threatening ones. The possibility of it bricking thinners and turning your Archespore into a 4 point play has been discussed at length.
Yeah, there are tougher targets for it to crack. Veil, any positive Exposed/Berserk effect or similar, but there aren't nearly as many of these as people think. High base power negative deploy has been cited as a "counter" but with sufficient coins they just die anyway and bounty replenishes the coins. Greatsword is the best case scenario, but then that's a big Graden next turn (as well as several other methods).
There's a sense that since SY is already broken rn, this card being broken but not auto-win broken (except in the matchups I've described) is somehow impressive. Yes it might not be the most busted thing in the game, but it's absolutely going in every SY deck and we'll lose one more interesting facet of deckbuilding as we adapt to it. I don't see how that adds to the game, and it clearly takes some things away.