My analysis of the situation, as a WHM, is that SE created an awkward middle ground for tanks and healers.

The 3.x situation allowed for substantial flexibility for both roles. Tanks could both tank and deal damage, and healers could both heal and deal damage, at virtually all content levels (provided they were reasonably geared / skilled). This generated interest in the jobs for many players, including myself, because we could push ourselves: optimizing damage-dealing while managing our primary role effectively was a near-endless challenge.

The 4.x situation removed this flexibility. Tanks take significant amounts of damage (at least through Castrum Abania; I haven't progressed further yet), which restricts healer flexibility. Their reduced damage also forces tanks to stay in enmity-generation mode most of the time, which reduces their options.

That's not necessarily a bad thing - but SE didn't account for the loss of choice. If enmity generation is supposed to be a heavy focus for tanks, where are the multiple rotations and toolsets built around it to replace the now-semi-useless damage-dealing options? If healing is supposed to be a heavy focus for healers, where are the interesting toolsets beyond cure-spam and standard HoT stuff, toolsets that have some benefit beyond keeping people above 90% HP rather than above 75%?

If SE truly wants to re-cast tanks and healers so they deal less damage and focus more time on their primary role, they need to do a more significant revamp of the skill system to reflect this change. We need to have interesting options that allow for skilled players to continually push their limits when playing these roles. What we can't have is the current f*ck-up, which is friendlier to newer players but insanely boring for others.