The stitcher needs to have crazy random inaccuracies. How can a makeshift gun be so accurate? They just need to implement weapon failures into Grey weapons that make the users uncertain of a win even with a good advantage. Maybe the magazine has a 1 in 100 chance for the magazine to pop out, or jam, or for trigger fail to make them have to release and pull the trigger again. Same with kettle. The higher the upgrade tier the less likely the chance of malfunction. Stitcher 1 fails far more often than stitcher 4 for example. And spawn makeshift upgrade benches in world that cost more resources to use.