Well since we're on the topic of "What maps do other regions play" they actually don't seem to play all the same maps.
Back when EU Forgotten was a thing, I used to spectate and record a lot of their clan battles, and I noticed that they do play some different maps. But, this was possible because EU Clan battles were almost always with 4 - 6 people, unlike US where it's almost always 8 people for a clan battle.
If you're wondering why having less people makes a difference, picture it this way.
If you read
Zoeticly post, you'd notice she said maps like Icarus and Solar Frost would be bad maps for having US Clan Battles on because they would be 8v8s and there wouldn't be enough routes for everyone, and everyone would be bunched up.
Now with EU, there would be alot less people meaning things wouldnt be to cramped with people.
Anyways, when I spectated EU Clan Battles, they played some maps such as
Wyvern's Wake
Icarus
Solar Frost
Chernoble 2015
Demon's Breeze
And some other's that I might not remember.
But it seemed as if alot of EU Players enjoyed these maps.
Although EU did play still play all of the "Always Played" maps.
So having a different thread for "Official EU Clan Battle Maps" would be somewhat necessary