There's no point in banning kyurem-Black. Right now it seems overly threatening to the metagame due to its versatility and the unfamiliarity of its use to the majority of the playerbase. Pro's metagame is similar to ORAS/Gen 6 with a few Gen 7 additions. There are plenty of checks and counters such as: Keldeo+Mega scizor, M Metagross+Keldeo, faster threats like mega lopunny, M medi, and latios and is constantly worn down by rocks. Although can argue that Magnezone+M scizor+Byu can threaten both m metagross and M scizor offensive cores with keldeo. Regardless, You're probably concerned by how Kyurem black threathens the popular defensive cores in the metagame such as: Amoongus Heatran and landorus, But the same argument can be made for the prominent wallbreakers that are currently being used such as Mega medicham, mega metagross. Ferrothorn, lando/chomp, zapdos core can handle both banded and LO sets without focus blast which will rarely be seen as they would either lose out on roost or substitute if they are using leftovers. As well as its unnecessity with the core of magne+Black Kyurem. An impish Mega Scizor with a 248 hp 16 def 244 spdef can effectively wall both sets of kyurem; which is why I believe there will be a rise in usage of ferrothorn in defensive cores and Mega scizors in offensive cores. People should be expected to adapt to the changes in the metagame as it will continuously evolve as the development progresses. Not to mention that Z moves are not in the game yet which would without a doubt, make Kyurem Black problematic. I'd honestly suggest releasing tapus and pex along with Z moves.