Even w/out knowing til later that Savage Blade generated more enmity I always used it over Riot Blade because its cheaper TP wise.
If you watch the Enemy List there are symbols next to each mob. A Square flashing red/yellow you have Agro. Upward arrow red/ylw means youre 2nd on its hate list. Downward ylw is 3rd after that it means youre 4th or lower. The symbol will change the INSTANT you lose agro even before it starts moving to new target. You can reclaim agro instantly by immediately Flashing, since all the enemies shouldve been near you anyways (creatures may still walk over to execute the attack it queued, but should immediately come to you or you shouldve moved to it & add either a combo or another Flash on it)
Run Qarn this will teach you where/how to move so that DPS always have the shortest time to get back on its backside (which should be the side facing the Healer as much as possible, exclusions apply) & not all bosses can be stunned find out b4 you stand ur ground.