Simple question, seems Cryptic hates Tanks and Healers [thats a very general opinion from chat, forum, etc].
As a former Tank [and now a healer] from before Mod 16 I can attest that end game stuff places a lot of emphasis on the Tank and Healer to be the best they can be, or its a wipe.
The Tank has to grab aggro, the healer has to time those heals almost to perfection on the real endgame stuff or its a wipe.
Someone said elsewhere something like "the healer needs to have the dexterity and reflexes of a 13 year old kid on a sugar high to heal through some stuff".
I agree, I can heal very well, know my place and for the vast majority of content can heal very well thank you.
BUT there is too much emphasis in Endgame stuff place on Healers and Tanks, and the failed runs are down to the failings of healers and tanks. Which means healers and tanks are also less likely to participate in end game stuff.. a cycle of doom as you can see.
The answer? Not sure... give tanks some real big hit points, defence etc?
Weaken the damege done in end game dungeons?
Lets talk abotu it sensibly like adults as the DPS community wont last long with unhappy tanks and healers