Skill or Feat?

I have been asked to post Degarren's character sheet on the chronicles, I will do so following the game today. I will also be posting an update of last weeks game including perhaps a pre-hack and slash monologue from the favored soul himself...not sure, I'm still toying with the idea.
One thing tho that I would like player input on however is something that has come up a number of times. Perception of power. Like was said in the 13th warrior, deception is the point, any fool can calculate strength. How would one know if a challenge is above you. How would you like to walk up to Royce (pronounced Hoice) Gracie standing at a diminutive 170 pounds and pick a fight. For those that don't know he's a multiple ultimate fighter champion. One bad dude. However he looks as though he'd be a push over. I have toyed around with the idea of augmenting Survival in someway or creating a totally new skill however the logistics would be challenging, such as new players not being privy to the same info etc. I've also considered a feat but quickly tossed that idea as there was too much stick not enough carrot i.e. it would be too costly a thing without much payoff. I am leaning toward the survival idea. I've also just considered making it a spot check by adding BAB or caster level. The idea is that fighters would be far better at gauging the strength of other fighters than spell casters and vice versa. The DC's would be similar to this:

DC 15-Is the foe injured, full strength, hindered, or aided in any way.

DC 20-Strength relative to your own e.g. undefeatable or insignificant.
This is not to say Bluff,Disguise, or any other form of deception
is not at work.

DC 25-To what degree is the foe injured or aided,
e.g. how close to defeat or death.

DC 30-Is the foe altering their outward appearance of power.
i.e. trying to appear weaker or stronger than they are.

DC 35-You can see precisely what kind of challenge or lack there of the
opponent is.

As you can see many of these DC's overlap with other skills like disguising your apparent power. A Sense Motive could sniff this out as well.
That being said I'm also considering handling this on an ad hoc basis with every situation being different. Ideas or input?