Here's how my Villagers view it. I'm also going to point out that I've had a Villager who had a gank-o-meter of 2.25, probably the worst of any Villager ever, but had no reputation as a ganker. But that's because Homard was almost always raiding, rarely just hunting. That, however, is a post of a different color.

This argument will be easier to swallow if we define a constant. Let's say that The Imperial War Master is a 1.0. Now, no Villager would ever consider himself to be a less capable warrior than the sniveling Imperial dog (even if they are an order of magnitude less skilled.) Resultingly, any Villager must automatically consider themselves a 1.1 or greater.

Now, if we're going to measure foes against The War Master, let's see what we come up with. Maybe he's an Imperial tool, but The War Master is still a man of blades. No mage can measure against a true warrior. Any mage must be a .9 or less, so because 1.1>.9, you can't gang a mage.*

Assuming the War Master to be the greatest non-Village warrior in Thera, all other warriors (and bards and thieves, etc.) will be .9 or less as well. Can't gang them. Ditto priests.

*Once in a great while a foe will arise who is nearly powerful beyond measure. Lichs, Mummies and extremely powerful AP's (there have been none in the 5th Age) can be ganked. If a foe is reasonably a 3.0, bring numbers to them.

Also, these numbers assume the foe is at full health. Ahteli might be a 5.0, but with 10hp, she's only a .2. I do my best to not engage anyone who is at bleeding wounds or worse.