With the sealed switch that is going bad, I would just buy a switch craft. and upgrade the output jack for a switch craft while you're at it. The control pots I would leave alone if they're otherwise functional. Maybe shoot some contact cleaner inside and work them around.
Locking tuners and a bone nut would be a good upgrade suggestion. I would go for whatever tuning machines come in a 18:1 ratio. One caveat with the bone nut, is paying someone to cut the nut and set it up for you. both those things you can do on your own if you're willing to learn. nut files can be expensive. What I used to do is wrap some sandpaper over some feeler gages (the longer varitety) file them that way. Not the most comfortable way, but it can get the job done.