As a GM, this is something that always preys on my mind, and I try to spread myself as widely as possible among the members of the guild without falling into the trap of only running content with the members I've known since TBC. However, one interesting thing I've noticed each expansion is that there's a fairly significant issue with respect to gearing people to get them ready for raids.
Standard 5-man setup is 3 dps, 1 healer, 1 tank.
Standard raid setup is N dps, (N+2)/4 healers, 2 tanks.
Because the number of tanks remains constant, each tank has a disproportionate responsibility compared to the other roles when it comes to running the 5-mans required to getting people up to speed. Based on napkin maths, I *think* it works out as If you were to take each DPS through the same number of dungeons, each tank would have to run N/6 times as many dungeons as each DPS; 12 DPS means each tank has to do twice as much work than a given DPSer, 18 means each has to do three times as much.
Obviously this is assuming only two viable tanks, which isn't *necessarily* accurate (certainly at the low end), but if people are completely devoted to their role, that's how it'll pan out.
I think that's a potential source of tank burnout that isn't hugely being addressed at the moment; the cost of giving sufficient attention to the guild as a whole. Not sure what the solution might be - flex dungeons allowing from 5-to-10 people, to allow more DPS to get in per-tank?
(In pure gearing terms, the fact that other non-dungeon passages to gear exist certainly helps, but as a GM, I'm also trying to promote community within the guild, and WQs don't lend themselves to that, elite ones aside)
I guess the sort way of putting it is this: As a GM, as a MT, I'm asking myself what is the best thing I can do for the health of the guild - in both gear terms and social cohesion terms - and broadly speaking, the logical answer to that would appear to be 'run lots of dungeons for everyone'.