Just fu** the forum of this game. Better make posts on reddit with ideas for improvement.
You can come up with the best idea you want, but there will always be a lot of people looking for reasons why it won't work, even if they don't see the development and know absolutely nothing about how the game is programmed.
Congratulations to this community

Nope, it would not be hard implement that because it works same as any other que,it will just match another criterion.
Nope it will not be hard make that in already existing instance.
You already have system of party outside of instance with your friends + with randoms in duty with same party wich work like layer.