Is it worth it to get heirlooms for a hunter/rogue?

I know that the xp rate is already x7 but I love world PVP on this server especially when lvling and I think i can just make a rogue and use the same heirlooms after as well. Should I just do this or should I spend my emblems of triumphs on something else? I currently have a warrior that is only 3.5k i gs. Is there a downside to using heirlooms on this server?

Well, if you see it as a downside, Heirlooms have an item level of 1, so it'll be harder to gear into RHCs if you're full of them, but you can always replace them while you're gearing of course. Now basically, just do what you want to do. I do suggest you work on your warrior, but if you really want to level a hunter then go ahead.