Unlike many guilds, my guild has never had a problem with finding healers in TBC. We have a ton of 70 shamans, most of whom are resto specced and on nearly all the time. We have a couple of priests with good healing gear. We even have some up-and-coming paladins who are in the mid-60s.
Instead, our problems are tank-related. Like most guilds, we have a good number of warriors, about evenly divided between tanks and DPS warriors. But our tanks seem to have fallen into the habit of mysteriously disappearing for days at a time, which has slowed their leveling speed. Two of our tanks are still 67, which kind of puts a damper on Karazhan plans. Two of our prot warriors are 70, but one let his game card expire and can't afford a new one and the other is only on occasionally. So as of now, our theoretical main tank is a feral druid. Admittedly, he is a very GOOD feral druid, and he is excellent in five-mans and heroics, but he's not quite confident that he can handle the big raid bosses.
Other guilds I've spoken to have reported similar issues. One has a shortage of prot warriors and is having difficulty in Karazhan with druid tanks, and as for five-mans, "we've got 20 people wanting to instance and 2 tanks online." Another has trouble "finding tanks that wake up in time for raids." The third guild has enough tanks right now, but the leader noted that they leveled slowly.
As I see it, the problem has three parts. First, prot warriors level slowly, so the first warriors to 70 are likely to be those who spec arms or fury and have the gear for it. Second, warriors are sort of gimp right now, and many warriors have switched to other classes, either because they didn't like being nerfed or because they had trouble getting into a guild as a warrior. And finally, most raiding guilds only needed two or three regular protection warriors for their raids. When forty people doing one instance with three tanks turns into forty people doing eight instances, needing eight tanks, there's likely to be a perceived tank shortage -- even if you have the same number of tanks you did before.
Have you noticed a tank shortage on your guild or server? What do you think players can do to make life easier for tanks?