RPPM sucks. Well, to be honest, it sucks just as much as every other change they've made to MoP. People hate RNG. They hate it actually from the very beginning of the game, because RNG sucks all the time, due to Murphy laws or whatever. And guess what Blizzard do? They implement more RNG everywhere.
My trinkets proc all the time when I cannot damage the boss. Now, with changes in 5.4, the situation will be even more disastrous. No, I absolutely don't want to play a damage dealer in such conditions, since I want my damage dealt is not being based over pure luckiness in stupid fucking RNG.