DTPS is gonna me more important than ever this xpac(and i agree to this point). However you can't argue that with the current numbers we have on the beta the way to achieve the lowest DTPS is with haste build(until a break point we yet have to find) so we can keep 100% bone shield uptime. The issue with this is as you said that bosses are diffrent, some bosses will hit you in rapid succession(such as Botanist) while you might also find bosses like Krosus which hit more rarily. I did raid testing with Kanj. And as he said we got demolished by the boss(and keep in mind we did 3 tank and stood back with the boss together with a pocket healer and still got destroyed).