This is my second go 'round with FF14, and I have never played anything but a tank (MAR-WAR), and since I am in the early phase for the second time, here's how it is according to my anecdotal evidence - tanking is a thankless job that you do because you want to see content, don't want to wait in queues longer than 10 seconds, and are OK with taking blame that isn't yours.

Bottom line, when you PUG tank in FF14, everyone is either dead silent or a vocal critic of your performance. That's life in the queue for a tank. The good news though is that as the content gets tougher, there's less dead silence and tons more criticism!! Oh wait, that's not good news, is it?

If you want more tanks, be nicer to the ones you group with. Period.