Enmity is still a thing because it determines who's being attacked, and there still may be some off tank mechanics here or there that target 2nd on enmity etc.

As for it dumbing down tanking, technically sure, but the goal from a min/max or high performance perspective was always to use tank stance and enmity combos as little as possible, usually only at the very start of a boss fight wasn't it? So I don't tend to see it as a huge loss. For tanking we still have positioning, management of defensive cooldowns and bilities, and now every tank will have something to help protect the party as well. The whole 'blue dps' thing, while I can see where people are coming from, I don't feel is quite true even with the enmity changes. Even before these chagnes you generally spent far more time doing your dps rotation than doing enmity combos anyway, unless you're a pre HW paladin and your only combo IS your enmity combo.