At the lower levels, it can be an hour or more waiting for a tank to come if you lose your tank during a dungeon raid. Often, you never get a tank. I think this problem happens because it's easier to get gear from a dungeon raid as a tank than as any other job because tanks get no competition. In every dungeon raid, either the mages or the dps have to compete for gear. The tank never has to compete. I've done enough Brayflox runs, for instance, to know that each possible piece, whether mage, tank, or dps, loads at around the same frequency. That is the problem and the reason why tanks are harder to find. A mage might have to repeat the run a dozen times to get his or her gear because he or she had to compete for that gear, let alone because it didn't load on that run. Tanks, however, get their pieces when they load.
So the solution is simple: lower the load percentage for tank gear. Make it something like 40% for mage, 40% for dps, 20% for tank.