The range rating will allow each outfielder to get to more balls. However, it will also result in slightly more "errors". The SIM has wacky scoring. In real life, if an outfielder made an outstanding play to just get to the ball, but was just barely unable to hang on, it would be scored a hit. In HBD, it is scored a plus play and an error. At the end of the day, the outfielders are still offering a net positve in the aggregate out there. Sure, maybe they miss out on a gold glove due to the way that HBD scores the fielding and maybe this needs to be updated, but if you have the luxury of putting big range or big arms out there, do it.