Except Articuno has a fire weakness, a rock weakness, is slower after an SD and KOed by SE/ Outrage/ Tackle, and is 4x weak to SR.
Tentacruel can come in on pretty much anything.... except specs Draco Meteor/ Leaf Storm.
910 Atk vs 372 Def & 364 HP (140 Base Power): 367 - 433 (100.82% - 118.96%)
remember I'm against this getting Draco Meteor. Take this, for example:
910 Atk vs 262 Def & 334 HP (140 Base Power): 261 - 307 (78.14% - 91.92%)
that's the solar power one.... on max sp. defense/ HP skarmory.
607 Atk vs 262 Def & 334 HP (140 Base Power): 174 - 205 (52.10% - 61.38%)
even without Solar Power, it forces it to roost or never come in again. Latias/ Mence were bad enough.... and they were only base 110. =/
607 Atk vs 262 Def & 334 HP (90 Base Power): 150 - 177 (44.91% - 52.99%)
That's modest specs aura sphere: and with Lilibelle around the corner, locking yourself into this is never the best idea.
Just some food for thought.