If they could make it work fuel and economy wise with a Classic from a driver's perspective it would be a lot easier as the classics have far more benign handling qualities in gusty conditions than the NG.
Reading between the lines, it sounds like the Comair crew who went in there (who I imagine were probably senior TREs/Performance pilots) weren't massively comfortable and probably want to develop a better knowledge base and a serious training program before making a decision either way. I am sure it will be a Cat C airport requiring special crew training anyway and they currently have a limited knowledge base.
Perversely, a heavier aircraft might make things easier for the crew than an empty one - below 60t the 738 gets significantly less stable in gusty conditions. Test flights in a Hercules would not necessarily have told you much as conditions a prop driven transport might find perfectly manageable could be a no go in a swept wing jet.