I have been naturally been going haste as my first secondary stat out of habit from cata but looking at EJ and top boomkins in the world it seems since the break points for haste are so far off without 4 piece everyone is stacking crit.
It seems like a very mathy question and the sims i use seem to be not quite up to date.
I know there are some really smart boomkins in these forums if you want to chuck in your 2 cents it would be greatly appreciated.