If you are trying to optimize BRD it is very easy to leak DPS - because if you don't hit the appropriate button for a proc on the same GCD (or sometimes half GCD), you lose DPS. If several things proc at once and you don't instantly respond with the correct priority, you lose DPS. If you do not care about this, then it is considerably easier to play.

If this doesn't appeal, DNC has procs with more friendly timing (they're on the GCD), and MCH has a set rotation with no variation, making it arguably the easiest in the game (Basically it's 1, 2, 3, 4... all the way up to roughly 20, then loop and repeat)