First off, i will say i feel your pain. PVP is very hit and miss for me too. Fortunately you have some good stuff to work with to make it better.
You need to focus some time on matador. Get him to 3 stars (shouldn’t take too long with dailies and pvp frags), get him to silver, and lvl him up best as you can. Hes a great front liner who has a great team heal and provides a lot more for the team than operator IMO.
Having matador and nightingale should give you some flexibility to add more dps and odachi is a solid choice.
Lastly, Maven really shines when she hits gold from what i understand (havent used her much). So until then, you may want to use someone else. Savage is one I would consider. Hes a solid dude and with him, butter, and matador at the front, your other 2 should be well protected in the back.
Just my 2 cents though and what I would try to do. You should also check out the latest ranking post for pvp from Rygel: Rygel's Rambles: PvP Tier List [PATCH 1.0]