Hello,
I am actually surprised that no one every mentioned this one. At the moment the fact that you validate the main quest in an adventure ejects everyone from it and sends troops and generals home, but with the actual system a miss click can happen really quick and having troops travel home 1.5h or even worth loosing loot is really a pain for just a miss click... The worst part is that you validate quests all day long and suddenly it can have a big negative impact without even a pop up saying are you sure you want to close the adventure...
What i am proposing would be that you can say "i am done in this adventure" and this even before the quest is completed ! And once every player has validated the "i am done" and the quest is validated only then the adventure would end.
This way everyone can validate the quest and terminate the adventure (if the other have checked i am done) so you can go afk and let someone else finish the adventure and everyone can make sure that they have loaded they troops and done what they need in the adventure.
And if you are worried by someone joining the adventure and going afk before checking the "i am done" button you can imagine a "throw everybody out in 15min" button for the owner of the adventure once the quest is validated.