Very good point, Gnarly. I'm a young-adult tank (lvl 21), and get plagued with overkill quite frequently... since I can't change targets and attack them as quickly as everyone else can (no range, sprint off so I can save end), I typically keep the big damage-dealing mobs (bosses, Lt's) occupied to keep the majority of the damage off the team. A good tanker will ignore the urge to be "everywhere at once" and take his beating like a man, and a bad tanker will hop from minion to minion and complain about the blasters getting credit for the kill. I don't know how many times I've been playing my blaster and watched the tank hop around and fight the minions while the boss walked to each one of us and flung us around like rag dolls.
Once the minions are dealt with, then the team can converge on the tougher mobs that the tanker couldn't take out because of his medium damage ability. Even if a tanker isn't able to do much damage to a boss or archvillian, he should have enough accuracy enhancements on his taunts (a good one will have 2 taunt powers before lvl 20, single target and AE) to keep the attention of any mob up to 5 levels his senior.
Do that at the very least, and there won't be a group unhappy with the way you play... well, won't be as many at least.
