I find it hard (short of going OOM) to keep from pulling threat on some fights ... others, like Loatheb, I seemed to go OOM quite a bit and struggle. ShoR can be crazy threat. Moreover, if your other tank is in on the plan, you can always do something like taunt and have it taunted back from you. Viola, big threat lead (like you need it?) and you're suddenly much closer than you might be if you're languishing. ... as long as they know the plan, hehe.
That said, I don't mind being OT on a lot of fights. Being able to throw Hand of Sacrifice for an enrage, locust swarm, or other high-burst mechanic is REALLY handy. (And, as a bonus, I get mana later!) This lets the other tanks benefit from my HoSac, and use their Shield-Wall equivalents before they die. Then, I can taunt and finish it off.
Also, sometimes OTing fights is more fun. I found that I rather like handling Gluth's adds.
On trash, it's almost hard NOT to steal aggro from everyone.... though warriors give me a good run if they've gotten in and blown multiple skills on a group of mobs. I sit back and save my mana for the next one, in that case.
also it can be used on MT and even if he loses aggro he can always taunt.
thanks for clearing that up 