Certain DPS specs get into dungeons much faster than others

I’ve been noticing this issue for about two weeks now and I’m 100% certain that certain DPS specs are at a disadvantage when it comes to dungeon queues. I’ve been using the anniversary event and timewalking dungeons to level several classes from 0-80 on the alliance side.

I’ve come to notice that certain classes/specs get into dungeons significantly faster than others. It seems like especially melee DPS gets in faster than ranged DPS and I’m just wondering why this is the case.

As an example:

Ret Paladin, Sin Rogue and Frost DK - I requeue for TW the moment I get out of a dungeon and I usually only have enough time to vendor my items and allocate new talents before the next queue pops. Often less than 3 minutes in the queue.

Destro Warlock, Ele Shaman and Balance Druid - I end up waiting way longer than the stated average. Sometimes 10 minutes upwards.

I’m playing all of these characters as DPS specs. I also doubt it’s about time of day or anything like that. I was leveling my Frost DK yesterday and today, getting dungeons within 3 minutes (3-4 level ups per TW dungeon). Decided to start a balance druid because Frost DK was boring to me. Immediately it takes 8-10 minutes to get into a TW dungeon. I went back to the Frost DK, which was at level 70, and immediately got a dungeon within 3 minutes, on the same realm.

So it seems like somehow certain DPS classes/specs are at a major disadvantage for dungeon queues compared to others and I’m not exactly sure why. Is it because melee DPS is being prioritised over others? Are you competing with other people playing the same class/spec as you and it just so happens that melee DPS is a minority? I can understand queue times being faster or slower depending on which role you play, but it’s strange that it depends on the class/spec within the same role.

I’ll just start queuing as healer to get faster dungeons, but it would be nice to understand why there is such a big difference here.