This is all with sPvP in mind!
I use a very similar build also, but switch it around a little bit, putting 10 points into explosives instead for the burn on crit instead of the points in invention. Then remove the cripple from Firearms for increased range.
In terms of gear I go with 4x Affliction and 2x Krait runes for increased bleed and poison duration and condition damage, with the generic earth and agony sigils on my weapons. For my accessory I run with Rampagers for the increased crit rating, then use the stacking might from elixirs to increase my condition damage a little more, the crit rating then correlating a lot towards burns and bleeds from traits and sigils.
Utility wise, I run with Elixir H for heal, Elixir B for self-buffing, Elixir R for the break stun, endurance regen and it's toss is amazing when you know you're going down. Along with Elixir S or U dependent upon the situation and the general team make up I'm up against.
In case this is a TL;DR situation, here's a link to what I'm running instead:
http://gw2skills.net...AjAGrPOYk MqYGA
I've found that I very rarely get downed, in bad situations you have Elixir S for invulnerability and toss Elixir S is also really handy for stomping certain classes, so it's what I generally run.
There are very few professions that I have issues with, aside from perhaps decent mesmers and thieves, but I think that's a general consensus (thieves not so much if I have Elixir S and Toss S available).
Good luck with the build! It's so much fun and a lot of survivability with supply drop along with it too.
~ Erien