Who Benefits from the Skeleton Key Nerf?

Nope, Will write it by N-th time. SK after 4.7 (or 4.8?) is no longer “early game weapon” as it requires new player to unlock most of kingdoms, before it’s avaible. By the time neded to make “SK team” you’re pretty much guaranted to earn EoE, and with EoE you can easily farm some lvl 20 delves and earn a nice team like:
EoE, Beetrix, Goblin Shaman, Emperinazara…

And time needed to get these weapon and 2 legendary troops is much shorter than getting that Thief class unlocked.

With resources needed to trait Cederick, you can easily trait Beetrix or Emperinazara, both of which
will boost your team (either giving you easy cleanse, or heavily boosting Beetrix damage with Empi)

If anything, this nerf will help early game players. Early in the game, when you dont have many stat boosts, fighting vs SK team could end up with a quick wipe out of your team… (2 casts of SK, probably even in 1 loop)