I suspect the real reason coil isn't on DF is because of the lockout system, I'd be annoyed if I queued on monday evening only to land up with someone saved till turn 4, not really going to make any progress from there in a pug and that's going to be that person's coil week wasted before it even started. SE could rework the lobby and separate the turns out so they had their own unique entrance and DF slot but given how often DF pugs manage to clear titan, I'm not sure that the work required would be worthwhile frankly.

As mentioned many many times in this thread. Coil really requires a fairly static team to make proper progression, DF can't provide that. Form your own groups and try to keep hold of people that do well. Get a linkshell going perhaps?