The good use of having a 14/52 is that i stunt, my fz and my zx6r. So it allows me to pop faster at lower RPMs or clutch in a higher gear. As for going down to a 15 it will give you a quicker take off, adding a little more torque.
I originally went -2/+1 but it wasnt pulling up in second with throttle alone, so i added +5 teeth :-D I'm happy.