Offensively:

You might want to change the bow to sharpened for more penetration.

On the bow bar I would replace Mark Target with Relentless Focus. If you're marking your target prior to sniping them you're just letting them know it's coming. The Assassin's Scourge hits harder than snipe and will help you with melee combat.

I would also replace Poison Inject with Silver Shards. It hits harder and the addition of another fighters guild ability will buff the bow/snipe/relentless damage.

On your 2h bar you'll need to replace D/Swing with Cleave to take advantage of the Master's 2h buff of that ability.

Replace Slimecraw with 1pc Kragh and 1pc Kena/Velidreth or Balorg. This setup out perfoms Slimcraw and it gives extra pen and weapon damage. Slimecraw really only gives you approximate a 6% increase. You can test this by getting naked and only equipping a bow. Record your normal and critical snipe damage, then do it for Slimecraw and then the Kragh/Kena.

Mundus? I'm assuming Lover for penetration as the only source right now would be New Moon and CP.

Defensively:

You might want to add some well fitted to the body pieces. Your best defense is not to get hit. Use roll dodge, stealth and LOS to avoid damage. Consider running Shuffle vs Rage Against Time, helps against Jabs, Leap, etc.

On my Snipe/Brawler build I run 2 well fit 2 impen and 3 divines and survive most outnumbered situations (until I get locked down and zerged).

Hope this helps, have fun and welcome to the world of salty whispers.

-Sola