I think B- would be better, but it's definitely a good mon atm. On top of what you said, it also has a priority move in Ice Shard which is great since Noivern and Rotom-C dropped. Sadly, Rotom-H dropped as well which it can't touch without running a rock type move or toxic and if you choose to do that, you lose either Icicle Spear/Crash or Stealth Rocks. Like Golurk, it has stab EQ and Ice is a nice offensive typing; but it has more than 2 weaknesses. It's weak to: Steel, Water, Grass, Fighting, and Fire (mitigated by Thick Fat, but it still can pack a punch). It also has few resistances beyond Ice (thanks to thick fat) and Electric (A nice immunity, but it's weak to coverage moves on 2 of the 5 main electric types [Flash Cannon on Magneton and Surf/Focus Blast/Grass Knot on Helioisk, Overheat/HP Grass on Rotom-H and Leaf Storm on Rotom-C]). It's also, like Golurk, nerfed by Knock Off, but it still retains average bulk after being knocked off. Hippo is generally a better wall, but Ice priority and the ability to run max attack without needing to invest in defense/SpDef is very helpful. Dragon types are slowly becoming more common in NU (and are becoming very dominant and will be until more fairies are released), so the Ice typing is very beneficial and the most used Dragon type, Noivern (rip Drudds reign although it's still in the tier, rip Goodra's even shorter more dominant reign), is quad weak to a Piloswine's priority move (Surprisingly, Noivern is bulky enough that it has a 30% chance to live at Full Health).