haxiom
God's not dead.
I actually think an example of one of the teams which does struggle with Geomancy Xerneas to some extent is the Ho-Oh webs team. Rocks+GeoXern pretty much wins, as GeoXern does get a free set up on Groudon, which I suppose could be played around sometimes but basically it means that you cannot get rocks up and you cannot use Groudon to check anything which makes you weaker to a lot of physical attackers like Zekrom and Ekiller. It's not impossible to beat, but it's definitely difficult and I'm curious to see what the counterplay would be.