What is the deal with queue times lately?

[Frizze]

can someone maybe explain to me how he dungeon queues even work?
It was a bit late yesterday but i wanted to do Copied factory, after 30 minutes it finaly started but somone declined (or was afk) then it didn't pop up again and the party was almost empty. shouldnt it just will up with one more person and pop again?
does it not keep people in line but replaces everyone randomly all over?
when i had 3/3 tanks, 6/6 healer & 15/15 dps, and then only 7/15 dps this is really strange, what happened to the rest when only one person declined?

So if you que as a group and one of your team declines, it kicks the entire group out of the que. Sometimes those people dont reque(so they just gone from que), sometimes they re-group and que. If their regrouping allows the matchmaking system to immediately form a group then that happens, often with some of the people from the previous group now left out. Theres certainly a lot more to it then that though.