http://img442.imageshack.us/img442/1659/lowthreatdeathclaw.jpg
Damn
I noticed that too when Kai said "Hey, upload some screenshots. AND DON'T SCAN GOODSPRINGS SETTLERS AGAIN FFS". So I went out to look for a Deathclaw, scanned it and threat: Low... sure...
So here's what I scanned instead: http://www.newvegasnexus.com/downloads/images/40040-5-1296575626.jpg
Anyway, the threat rating currently is just a level comparison:
if curTarget.getLevel > (player.getLevel + 1) set threat to 1 ; HIGHelseif curTarget.getLevel < (player.getLevel - 1) set threat to 3 ; LOWelse set threat to 2 ; MEDIUMendif
Seems like you outleveled the deathclaw!
E: I'm open to suggestions for more sophisticated thread estimation methods btw (as long as it's feasible)