For dps those queue times sound about right. I generally try to queue with a tank or healer friend to help speed things up on the ex. roulettes and whatnot. If I'm levelling, I'll either queue in a partial premade with someone else who's levelling a class that helps flesh out the trinity a bit more, or I'll spam fates in the meantime.

I tend to side with what nearly everyone else has said here; the DF is data center wide, which means that it takes from every server in the data center, even (and especially) the higher population servers that likely have more players needing those dungeons for whatever reason. The problem isn't that the server population is dying, it's that the particular roulette isn't as popular as you'd like it to be.