If it's broken, then we while testing this out on Shoddy we can change it. And yea, bulky waters, Bronzong to some extent. The only good moves this thing really gets are Bug Buzz and Blizzard, and the rest of his coverage isn't amazing. It hits some walls, but gets walled by others. Just like Heracross being walled by Gliscor, but still putting the hurt on many Cressys.
Once you have Buzz and Blizzard, the set almost has to be entirely special or have two more physical moves. If you've ever used a Yanmega, which has comparable special attack, but not had hypnosis, then you'll pretty much be looking at a purely special Syclant. You need Brick Break or Superpower to hurt Blissey, and even more Superpower. Dont' forget about Superpower's Attack Drop, so maybe then you could put on Earth Power, or something. This sample set can hurt some stuff, but not everything. The thing about it, it isn't gonna be OHKO'ing anything, and with its defenses it gets killed pretty easily. It's no more broken than Medicham with Compoundeyes.
I don't know about how 'broken' Mountaineer would be. I mean, if you use it, you're restricted to Ice Beam, and other lower power moves. Part of this thing's potency is its ability to use Blizzard with impunity. So, if it's using Blizzard, 90% of the time Stealth Rock will rape it. I don't think it's too broken as it stands.