It won't take forever, but it can slow the fight down as much as waiting for the cutscene to finish would have.
Unfortunately, that would defeat the purpose of the Roulette, which is to ensure that there are enough players to fill out the remainder of a group for every new player trying to complete the storyline. The Roulette needs to be able to assign you where it needs you, which may be filling out the one last open spot in a group.
That also has to do with the fact that new players are (by SE's design) supposed to use Duty Finder. That's why the Roulette was added to DF. If new players were supposed to use Party Finder, then SE would have to find a way to redesign the Roulette to finish off PF parties rather than DF ones.
