Totally unneccesary move from Blizzard to change every single specc to reaction/priority based. For example, i really liked the Frost-DW armor penetration build with glyph of pestilence. Really tight rotation with a 1 sec frame at the end of the cycle to refresh deseases by pestilence. In essence it wasnt the hardest thing to play the rotation correctly, but applying it to every single situation in every boss fight was the skill cap; and i liked it that way.