Let’s do a quick and basic rundown on how to setup and use a threat meter. We’re going to use Omen for our demonstration because that’s what we like. Our blog, our addon, our post, right? Right.
Download Omen, install, start WoW, look on your minimap for the Omen icon and click it. Poof, your Omen meter header will appear:
Tada. Now we want to ensure that it is always On when you’re pet is out. Right-click on the title bar there and select Active With Pet:
Very nice. Next we want to take a look and see what the threat-bars look like. Select the Show Test Bars option and lets see what happens.
AUGH! TEST BARS! Don’t panic, it’s alright.
We’re going to make our pet’s bar green. Green is good, right? Right. When the bar on top is green, we’re good! In a future post we’ll make the Main Tank’s bar green. With a whole raid on the meter, it’s really easy to see if the MT is on top if you’re always used to seeing a green bar heading the list.
Right-click on your pet’s bar and change the bar’s color.
Poof, it’s green!
Now we’re going turn off the test bars by selecting Clear Threat. Good job.
Right then. Next we want to turn off the Aggro Gain bar. We’ll discuss what it’s used for in a future discussion, but for now it might be confusing. Click on Display and then uncheck Show Aggro Gain.
And as long as you’re there, go ahead and select Show KTM Data. You may have people in your parties and raids who use the KTM threat meter and this option will allow your Omen to process their KTM messages and incorporate that data into your threat-display.
Select the Close option and you’re ready to test it out!
Find something fun to kill. We’re going after the moths outside of Shattrath City. Send your pet with Growl and let him attack. Your Omen display will begin to calculate that mob’s threat list.
Oh, look look look! Not only did it start calculating the threat list, but the title changed! Omen will keep track of multiple threat lists by mob-name, isn’t that handy?!
Note: if you have two mobs of the same name, Omen combines the data of both mobs into one threat-list. Watch for that; it can be confusing.
OK, now start attacking that mob yourself and watch the meter.
Notice that Omen is collecting our threat info and displaying it with our pet’s. Right now, Hobbes threat is higher so it is on top and at 100%. Since we only have 2k threat versus Hobbes’s 3.4k threat, we are at 59% of the mob’s threat.
2000 / 3400 = 0.588 or 59%
If we had 3.4k threat, matching Hobbes, we would have 100% threat as well.
Now as a ranged DPS class, we won’t surpass Hobbes on the threat list and grab aggro until we reach 130% of Hobbes’s threat. At 3.4k threat, we’d need 4420 threat to grab aggro at this instant.
Look at the TPS column, that stands for Threat Per Second. Hobbes’s threat is increasing at a rate of 423 threat per second while our threat is increasing at a rate of 471 threat per second. If our respective TPS rates remain constant, we would eventually surpass Hobbes and grab aggro because our TPS is higher than Hobbes.
If we were to Feign Death, and not be resisted, our threat would drop to zero and our bar would disappear from the chart.
One last thing, let’s open up on a new target, but let’s open with an Aimed Shot. Watch what happens to the Omen display.
Blamo! Our Aimed Shot crit completely blows away Hobbes on the threat list and we’ve got aggro. We are at 100% threat because we are at the top of the aggro list, Hobbes is at 48% and climbing.
Notice that we stopped firing and our TPS is now zero while Hobbes’s is at 250 threat per second. Hobbes will need six seconds at his current TPS-pace to equal our threat and begin to complete for aggro. Hobbes, as a melee class, needs to exceed our threat by 10% to get aggro back, so he’ll need even more than six seconds to push us from the top of the threat list. Hopefully you see why a Feign Death at this point is our most efficient method of allowing Hobbes to get aggro.
That should cover the basics of running Omen, we’ll do more in-depth use and analysis in a later post. If you have any ideas or things you specifically want covered in such a discussion, please comment. 
You might consider it too much automation, given your view on the castsequence macros, but I’d be curious as to your opinion on it. It’s new and I’m still working out any remaining kinks, of course. No software is ever completely free of bugs 
