Balance teams love Kyurem though. Kyurem typically fits best on teams with Gking and Corv - Pokemon that aren't best known for being HO staples. These teams are best able to pivot Kyurem into advantageous positions where it is able to fire off Ice Beams / Freeze Drys. Being weak to hazards in a meta where hazards are impossible to remove is a big issue though Kyurem can somewhat make up for this with Boots + Corv / Tusk support (not a fan of Tusk + Kyurem structs tho due to the massive weakness overlap).
Furthermore, balance teams are typically able to slot in stronger checks to kyurem than most other styles. Garg, Clefable, and GKing are great checks on balance that I am running for more than Kyurem.
Other styles have good checks too. Bulky Offense has good checks, including Volcarona, AV Iron Crown, Gking, Balloon Gambit, ballon Ghold, AV Hatt, etc. And stall to my understanding doesn't struggle with Kyurem either.
Kyurem's set variety and Freeze chance are factors that arguably push it over the line. I'm still 50/50 on how healthy I believe it to be, but it would have been a better Pokemon to suspect later. Its very difficult to see Kyurem as overpowered when Raging Bolt exists, has a better typing, priority, Calm Mind, and Protosynthesis Draco Meteor or weather ball to nuke every "check" on balance, whether it be Ting-Lu, Clodsire, etc. Out of the 6 "OP Dragons" (Kyurem, Dragapult, Roaring Moon, Raging Bolt, Gouging Fire, Archaludon) I found Kyurem to be the most reasonable one to deal with. When 5+ more Pokmeon are more broken than you (including others like Waterpon), it becomes difficult to confidently that it is broken.