Lots of great info here. With the non-functioning search feature of the forum, it is so sad this drops off the front page and is frequently lost. Shame on Blizz for not getting the Sticky feature working after all this time.
1) First get to 17% spell hit (1742 hit rating, 1639 for Draenei) and 26 expertise (540 expertise rating, since we get 8 expertise from Unleashed Rage).
2) Agility > Mastery > Crit > Haste > Hit (until hard DW melee cap at 21%) > Intellect
Current simulation suggests this advice is not "the best".
Adding stat A is frequently done at the expense of stat B by choosing a piece of gear, a gem, an enchantement or a reforging over another. Focusing on hit and expertise gear at the expense of all other choices in order to reach those caps will actually cost you DPS.
The only no-brainer in enhancement gearing is Agility. Depending on your current gear, even something like Strength can outperform the same number of points in hit, expertise or mastery (yes, even below the spell and dodge caps.)
Hit, Spell Power, Intellect and Strength are all clumped together in terms of affect on DPS, point-for-point. This is why we are now seeing more "unintended" gearing and spec setups as people find the time to experiment.
Until Blizz comes to their senses and fixes the huge dependence on spell damage, there won't be clear "best" stats other than AGI.
I would change the advice to say that once at the spell hit and expertise dodge caps, the value of these stats really drops. No need to go out of the way to "get" these stats, but make sure you don't exceed the caps.
The best advice in the OP for enhancement is the attack "rotation". I tried a bunch of different priorities and the one listed here is, by far the the one that pumps out the most DPS.