The role was still present in a pedantic sense, it was just shared across the board or mostly replaced by the PLD. I have not looked at the logs but I suspect the PLD did not have to clem spam because their normal sustain coupled with the rest of the parties sustain was enough.
This is the balance dilemma, I bet if a DPS had any means to reliably hold aggro and have some decent mit people would be trying to push content without tanks for fun.
Edit: What I am saying is I do not think this would have been possible without something taking over the healer role. So it was possible just not with a green healer, but some form of healer or healing was present.
