My first thought was about stun. Last year when Llama-kron became very popular in bronze becasue it was unbeatable, the answer given to new players by higher level players was "llama kron isn't even that good, just use an early stun". There was only one stun card in the whole game in bronze level and it wasn't early enough.
The play testers (mavericks) and the dev team do sometimes forget about the bronze experience.
It affect not only bronze league, also rulesets like "Monster loose all abilities" won't be possible if one of the players has a sneak, snipe, oppurtunity, stun ... quest.