We've taken trips ranging from 8 nights to 14.... 14 nights is a long time, but its not too long if you love WDW. Plenty to do, and it gives you some time to relax as well.
If it were a difference of a night or two, I might opt for the shorter trip with the better location. Say 12 nights at BW over 14 at FQ.
But for the options you provided, FQ for 14 would be my choice. You can always spend a few evenings having dinner and checking out the BW, WL, etc.