Could we get the remove from dungeon timer either significantly increased or made into a prompt for consent? Perhaps if you're kicked from group it can remain non-consensual, but in the case that the group disbands I think it would be very valuable to be able to remain in the instance. Many of the instances contain quests, and typically a player is not able to listen to/read these quests if they've joined the dungeon through the group finder. Perhaps we're intended to do these quests by seeking out the dungeon manually in the overworld? In this case, I think quests should be disabled altogether in the group finder.
As it is, a new player completing a dungeon for the first time might follow along with the quests story (no doubt lagging behind their rushing group, but oh well) and then right at the end they're faced with the situation where they either just sprint at the NPC and press "EEEEEEEEEEEEEEEEEEEEE" in the hopes of completing the quest before the boot, or, more likely, they're unaware of the impending boot, and listen to the first few moments of dialogue before being booted without completing the quest.
This seems to me like a glaring oversight to me, and is a nasty example of the game putting it's worst foot forward to new players.