A diskbrake is needed the most in GS150. I experienced that it has horrible (disastrous) braking power considering its size, and power. Plus, the rear type definitely need to be changed to a deluxe one for extra road grip.
I don't see the company doing this in near future. They can't drive down their profits when they are barely selling their current GS150s as compared to Hondas and Chondas.