I PuG exclusively, and from time to time I’ll join a group as dps, however if I’m tanking, which mostly I do, I tend to form the group myself.
I’m not 60 yet, but my experience so far has been relatively similar for forming groups on my level 40 Warrior as tank or dps, as it has on my level 22 hunter (obviously only dps).
As I level I tend to add friends to my friend’s list, particularly healers who I have run several instances with where we seemed to have good affinity.
I can imagine though that from 40 to 60 the number of available tanks was likely much less, will start to increase somewhat now that the more casual players, like myself are in their 40s and 50s but also may not increase drastically for a couple of main reasons:
1.) As we get higher in level, talent choices start to have more of an effect on our ability to perform certain roles, and open world questing as a tank doesn’t seem like something anyone wants to do.
2.) Most guilds that I’ve seen seem to have low priority recruiting for tanks, as oftentimes (it seems to me) they have sorted that out prior to forming their guilds. There are a lot of spots available for DPS (warriors) in Raids, and only 1 or 2 for Tanks.
And this could be true! I was running SM Cath with an rdru, enh sham, another warrior, and a rogue and we were steamrolling it, without issue. Very fast, back-to-back resets, pulls, and runs.
Took a break, came back and reformed a group (different composition, different people), wiped like 4 times before even making it to the boss, 3 people left, and I again reformed the group, but this time put on a shield and one hander, and slowed things waaaay down.
Group composition makes a pretty big difference, but so do the individuals behind the characters, and it’s sort of easy to get used to a certain cadence, especially if you run the same instance 10 times with the same group.