Again Theo.... is is part of that feedback loop.
One of the complaints in previous expansions was that certain tanks were just not brought in to certain boss fights. They weren't "ideal". So sayeth the hardcore crowd. Thus, if you weren't bringing a paladin tank or a healer of a specific class to a certain fight, you were labeled as fail. Or a group just didn't bring that class period. If you played that class.... awwww too bad. Sucks to be you.
So Blizzard responded by trying to homogenize the classes so that certain classes weren't relegated to being useless. Mind you... this was directly in response to theorycrafting and the various analysis done by the players (which was done originally due to the dev tailoring fights that favored certain clases).
Now.... people are unhappy that things are homogenized. Which is.... in a way, part of the push for making smaller talent trees with more immediately selectable specializations. Meaning, healer A can now be more specifically tuned to do X better. This is creating a sense of uniqueness..... BUT... at the root of it.... there's now even less specificity for the class versus other classes. You're no longer locked into one or two specs.... you can alter what you are at will, which means really, you're further homogenized.
And, what will happen in turn......
Theorycrafters and hardcores will go and determine that X spec for class A is the optimum for encounter Z. If you're not running in X / A / Z configuration for a certain boss.... thou shalt be labeled as "fail". Because you're not maximizing the total potential of your toon. Because if you really wanted to win and compete at the highest level possible, you'd do it.
This will in turn compel Blizzard to do something else in response. Heaven knows what that will be.
No one tanks in a void.........