The pre-amps are a notorious weak point on these, and replacing them, or re-wiring the bass as passive, are both common options. I have a Nordstrand 4-pot in one of mine which is a vast improvement over the standard, I've also fitted Artec cheapies as a short-term. The pickups are perfectly OK to run passive.
This looks like a later model with the preamp all on one PCB, earlier ones had individual PCBs on the pots which were much easier to just replace a pot. It should still be possible to replace a single pot without a complete rewire but the question is really whether it's worth the effort.
Not sure a right-angled jack plug is going to make a lot of difference. Because of the recess around the socket, it would only be able to point downwards, you'd have an even bigger loop of cable going down out and back to the strap. I've not seen similar issues with contacts on any of the ones I've owned.