In general, I feel that a low time FO is not a safety hazard alone, but when combined with an inexperienced captain, it is a recipe for disaster. The problem lies with the rapid upgrade times. A 1000hr FO knows enough to watch and learn for a few years. However, he will not learn enough in two years to then be ready to captain the ship with another 1000hr FO.
I think you find a safer approach to flying at places like Eagle and ComAir (despite the Lexington accident) because you don't have low time upgrades. Same applies with the major airlines. You are going to see places like RAH and Skywest develop a safer approach to flying as the sit in the right seat grows from 2 years to 5.
As for 250 and 500 hour FOs, well that is just stupid. I have seen those guys fly the heck out of the sim, but they just haven't seen enough to develop proper reactions to sudden events, or thorough thought processes for handling complex weather or rerouting situations.
I think that part 135 PIC minimums ought to apply to part 121 FO's as well. If you aren't ready to handle a cherokee with checks, you aren't ready to wrestle a Dash 8 or a CRJ full of people. Also, if everyone had to acquire 1200 hours to make it, the herd waiting outside the gate would be a lot thinner.
