So earlier today I ran with a tank only group. Clearing both Heroic Taloc and Mother after a couple of tries.
We then went on to try and clear Fetid and Zek'voz. Unfortunately there were some people screwing up tactics (IE not moving with beams) and some people not focusing the adds on fetid, so we wiped a few times and the group fell apart.
But it's an interesting proof of concept. The DPS is just high enough that it is manageable due to lack of healers, and the massive abilities to self heal and mitigate damage allowed us to trivialise some mechanics that would normally cause the deaths of DPS or Healers.
I was slightly surprised to see tanks screwing up mechanics on the 3rd and 4th boss, seeing as tanks are usually held to such a high standard, but there you go. We even had people running TOWARDS cudgel of gore -_-
If you're interested in seeing the cut down version of the video just showing the success on Mother and Taloc then I uploaded it to youtube
If you want to see the full stream it'll be up on my twitch for as long as vods stay up, if you're interested in seeing the proof of concept on Fetid and Zek'voz. (though zekvoz phase 3 might have been impossible)
https://www.twitch.tv/videos/317867084