Quoted from bonzo71:wondering if there is an easy, but permanent repair.
Yes. Get a new blade, or at least partial with the lug, and disassemble the switch stack and solder it to the broken blade.
Quoted from bonzo71:Would it be wrong to loosen the switch stack, insert a new wire and then re-tighten it and solder to the broken wire?
Probably. Best get the wire soldered to the blade, not pressure fit.
LTG : )