In reading through the thread, it sounds as though you are not yet comfortable with reading EM schematics. If that is the case I would recommend only fixing those problems you currently have. You are likely to create additional problems in the course of doing a full tear down that you will have a hard time locating and solving (oh, -this- switch is never closing, whoops!).

As you become more comfortable with working on the games, the appeal of cleaning every switch becomes greater. However, in my opinion, there are vanishingly few instances where it is truly necessary. Most of the switches are self-cleaning (when adjusted properly).