I know you won't like this...
You could try this for a while but with burning being our only condition and the time it lasts isn’t all that great for putting so much into condition damage. I only see condition damage being really useful if you can put 2-3 out with every few hits (such as scepter on a necro). Its not that its a bad idea for guardian, I just think there are better options.
Here is what I do that might interest you:
I’m full PVT, I run “Save Yourselves”, Signet of Wrath, and “Stand your Ground”. I’ve been playing with healing breeze over shelter but I’m not sure which I like more.
Anyways, the Signet of Wrath plus Wrathful Spirit and Vengeful makes for some pretty good damage output on top of the physical damage I already do.
Keep in mind too that this is for small and large scale WvW.
There’s a stickied thread about Burning right up there at the top: Pyroclasm.
And it’s definitively been determined to not be worth it.