They need to open it to every instanced duty they have.

I really wanted to use some of the Raid/Trial stages, but I need to normally queue for it (if not soloable), clear the encounter, just to have access to the stage empty.

Most importantly, Alliance Raids. You can't even enter them alone unsync'd to clear and gpose... gotta bother 2 other people to form the 3 Alliances. Most of them aren't soloable to do that, though.

I do wonder... is that hard to implement Explorer Mode to other duties, or it's just that they don't care to do it?