Unlike an air carrier, pilots at FedEx do not interact with our constomers on a regular basis. We don't make funny intercom calls in flight nor stand by the cockpit door as the boxes deplane and smile. The primary concern when hired is technical competancy and trustworthyness. Personality goes a long way in life, but it should not and does not take precedence over your flying skills.
My heart goes out to anyone who busts a sim. We all have bad days...lord know's I've had more than my fair share of them. I have a close friend that busted the sim the first time and he went through round two and got hired. I supported him 100 percent. That said, I don't think that there should be any exceptions made for a great personality. Either you have the proficiency or you don't. If you can't pass the sim the first time, then do what you need to so that you can the next time. Extra sims, more flying, stress management techniques, what ever it is that you need to correct.
We absolutely should not be hiring people that, for whatever reason (including a bad day), fail to demonstrate a minimum level of flying proficiency.