Well, i agree. I had the issue with beeing 14.50% hit cap, or 15.50%. Wich was way to high hit cap, or to low on hit cap. And i wanted somewhere between 14.95%-15.05%. And only way i could sort it, was using expertise/mastery gems in red socket. Tier 16 dosnt come with hit, and neither blue sockets, all is red socket, except legs, wich are both yellow. So you might want to balance them with expertise/mastery gems because of the items having such huge stats when you are reforging. But i trust brusalk when it comes to his testing. And he found it to be mastery/critical.
About haste, ive never tested it myself, but i belive haste was so good in 5.3 was because of how ROF worked.
But now With 5% haste buff from SP, backdraft and hero, im at 1.0 sec cast incinerate, with 2500 haste. Any more haste than that i would hit GCD cap, its just painfull to play with an incinerate at 0,6 as i had in 5.3. In the end, i just reforged out of all haste, because i hated that playstyle, spamming ROF like a mad man and those fast incinerate.
Now I am running with gosac, wich makes haste even worse if im not completly wrong. But then again, im just running Normals, and i dont need to get that last extra dps. And i kinda like the high HP from GoSac and SL