I agree that JF-17 needs a greater payload. However, you have to remember that adding missiles or bombs to a plane will change the whole aerodynamics. The current structure of the airframe will be frozen till some time. Increasing or altering the payload will be considered in the consequent batches of JF-17. It's widely known that PAF desires JF-17 with greater payload, range etc. It's a whole process that will require going back to the drawing-room.
First, the factory in Kamra needs to start producing a dozen Thunders. It's an absolute must to give the local aviation industry a kick start in the right direction. That is priority number one. Additionally, we need to start the process of phasing out and inducting the new platforms. The aging obsolete fleet needs to phased out ASAP. Gaining a wealth of experience through the domestic industry will inevitably lead to a lot of creative ideas and improvement. It can be used as input for the newer Block of the JF-17. Nonetheless, this is a pretty good idea and I commend your creativity.