Ofcourse a 2500 will tow better and ofcourse a 1500 will get better MPG (non-towing) and ride much better. You need to weigh out how much you tow with how important mpg and ride when not towing is. Sure seams like a lot members on this forum push people towards heavy duty trucks. Maybe because they are retired and don't need to suffer the daily driver MPG and ride?
IMO, 6700# is fine for that truck. I also HIGHLY doubt you adjusted your WDH for this truck. If you hitch was not setup correctly, the test drive with the trailer was worthless.
