I've played all tank sets and I have never had issues keeping the mob's attention only on me. Use the taunt power for those ranged guys that are hitting on your back line. Use line-of-site to make the mobs come to you. Once they are in melee range your taunt aura will handle the rest. If you are playing with a tank make sure you give it a sec before using all of those AOEs. I know it's fun to make the first hit, but it's more fun to have them all grouped and then use those AOEs. When I play a tank, my taunt is the most used power, that thing is always on cooldown. Nothing is more frustrating for me when I'm on a team than before the tank even runs in, the troller is throwing cages, let the tank group them up, then use your cages. Once those mobs are caged near the tank, the blasters and scrappers can do their thing and unleash the beast! As I tank, once the mobs are almost done I leave the team to start grouping up the next mob. That way they are in place as the rest of the team is done with the last set of mobs.