Gun Jumpers are so fun..

[Maelwys]

lately ive had brd that rush in full buff and just unload when i get 1 single tomahawk off. even with a relic, that doesnt produce some massive chunk of instant emnity

In those situations there's only one thing you can do:
Step #1: Stun the mob the DPS is "opening up" on. Then pop a Damage buff (FoF/Berserk) and Flash to get hate on the "other" adds.
Step #2: Use Fast Blade/Heavy Swing on the mob
Step #3: Once the DPS has landed their second/third attack, Use Provoke (Off GCD) to put you back on top of the enmity list, immediately followed by Savage Blade/Skull Sunder, then Rage of Halone/Butcher's Block.
Step #4: Flash.

Hate is now back on you. Enjoy.