Kyurem-B is just another pokemon that makes stall unviable in this meta. Genesect does have trouble with its most used sets, but it does have both Iron Head and Flash Cannon in its movepool, so it will be able to take it on. It's a great pokemon, but its typing is going to be its downfall. Because it's weak to two common priority attacks, and stealth rock it won't have a lot of opportunities to really spam attacks. It's best just to use it early game and spam Outrage. The only way I can see it being used later on in the match is if you EV it to be a bulkier set and give it subroost.