Kyurem-B is a powerhouse, but he's incredibly subpar compared to some of the other threats in OU. Other offensive teams just overwhelm it and his low usage only proves how ineffective it is. I'm not a fan of an offensive metagame, but I don't think Kyurem-B is broken enough to warrant a ban.
I guess Kyurem-B's suspect testing wasn't a bad thing, however I clearly do not understand intentions in background. The OU's metagame annoys me again, with or without Kyu-B. And he is not even as good as hoped. I expected a monstrous brokenmon, in the end, it's just one more (Genesect *cough*).
Unban or ban, doesn't matter to me, because this suspect is not the good answer for the good question ; how to make an enjoyable metagame.
In fact, I don't care about Kyurem's unban.