Basically that

Alliance raids have some of the prettiest and original places to gpose

Dun scaith final boss arena is one of the best in the game thanks to the moon and tower

Ivalice in general has a great aesthetic

Nier surprisingly gets a bit limited on it's third and can access the first one from the overworld

And myths of the realm, Eurosphine it's beautiful, but due to the fast exchange between areas it's kind of hard to try do anything

So, why after so long we still cannot explorer mode these?

Rather than a complaint it's a genuine question on just, what's stopping them from adding said function to alliances, even more so i'd think the demand would be a bit up