Is it safe to drop my mastery that low for hit? I know it's a redundant question.
i'm only recently a convert to hitcapping (again). previously, i let mine slide down to 9%. i've seen it said that the 12% area is the choice spot if you're not capping. and i've looked at that parse you provided, and you missed basically nothing.
but you're wondering how these other two cats are throwing down harder than you. from a personal standpoint the first thing i'd do is be as close to them as possible. what can i change on the fly? my stats. my uptimes. pour over how they use their cooldowns. do what they do.
if i'm still getting outplayed, then it's more than just numbers. and that's something else entirely.