I understand what your saying, but thats what tier/season gear is now. Of course there is still specific gear like primal mooncloth and FSW. So while I partly agree with you, I don't think it will be as bad as you think.

That is already the case with druid bear tanks. There is basically a straight line of gear with very little variation (it's only up the raid ladder you replace gear). So bear tanks look the same in bear form and out of bear form.....

It's not just bear tanks, pretty much all high-end raiders have identical gear, under ideal conditions.

Best-in-slot is just that.

Actually I think it'll work the other way. It would offer GREATER variety in stuff to wear. There's a bunch of designs out there with similar stats, but they're all geared to a specific classes needs. By homongenizing the way the stats work it'll allow people to use a greater variety of things. I personally think they could take it even farther. Here's an example

Instead of actually getting gear as drops you get gear enhancements (Basically the gear stats) as an enscription/scroll/enchantment/armor patch, whatever. That way you can choose or craft the gear you want for the look and still upgrade the stats via drops, badge loot what have you.