(Forgive me for necro-ing this thread, but it seems like a potentially interesting conversation)
It's been said more or less throughout this thread, but in my own words:
Scar is what teenage girls want the Predator to be.
This is what the Predator actually is.
Also, one thing I noticed no one mentioned is his eyes. Scar's suit actor didn't wear contacts (to my recollection) and therefore gave him a more...humanly emotive look rather than the colder and more menacing eyes of the previous Predators.