You're right, it's not the number of hours, it's the quality of flight time that's important. The biggest problem I see with new FO's is radio communications. Often they're not aggressive enough in trying to get a call in (SLC ramp). IMO the best hours a flight instructor can get is working as a CFII doing the cross country flights into busy airports. There's only so much that can be learned teaching turns around a point and lazy 8's for 700 hours. Being a CFI will teach you a lot about being assertive in the cockpit and that will be a necessary skill once upgrading to captain. I hope the interviewers are taking a hard look at what type of flight time the lower hour applicants are getting.