At the very least, I've always thought the game should do like World of Warcraft did when its cross-ream duty finder was first created years ago. In that game, when you are in a cross realm duty group, you can queue for a new dungeon without leaving the first one. So, if you are farming tomes or level grinding and you meet a really nice tank, healer, or dps who is doing the same, you can re-queue for another dungeon with that person. I've had leveling parties in WoW where myself and 4 strangers gained 20-30 levels by clearing dungeon after dungeon, progressing through harder content while constantly upgrading ourselves and our party.

I remember my first awesome dungeon group in FFXIV was sad because of the sense of one-and-done about the whole duty finder system here.