Through my Expanded testing, I have come to the concerning conclusion that Glaceon GX is extremely strong. In Standard, the deck certainly can run into issues with all the new metal support, that will certainly create at least one top-tier archetype, but in Expanded metal is much less of an issue and as a result, Glaceon is free to provide a strong lock at very low commitment.
Remember that this lock is a little different from other ability lock cards like Garbodor and Wobbuffet, because it does not lock the user out of their own abilities (as Garbodor and Wobbuffet do), and it does not allow opponents to still use Tapu Lele (as Wobbuffet does). Along with that, it is easy to achieve on the first turn; in fact much easier than it is for Trevenant to get the T1 item lock. 200 Hp is also much more to overcome as compared to any of the aforementioned Pokemon. Recall that the biggest reason Trevenant is not a problem right now is that it has a weakness to Dark types, meaning Zoroark can run right through it. Glaceon’s weakness to metal is currently irrelevant, it might as well have no weakness.
Rough Seas is another very important addition in Expanded, giving Glaceon some of the same benefits Wailord holds. Glaceon gets pieces of every denial/lock deck to combine into this monster of a deck. This is my present list for the deck: