If you want to pvp as itos currently is you'll probably want to take cannoneer for the 60% block pen attribute.
Musketeer has better single target but good luck hitting an enemy with the stone skin buff.
I really wouldn't recommend going rogue 3 for pvp unless you're investing in a r8 class, burrow is a fairly niche skill thats only real purpose is to let you easily solo bosses and the base damage on vendetta and backstab are nowhere near r7 class standards.