This is how it looked:

Step 1: desolder, open switches, clean, lube

Step 2: wiring

Step 3: wiring done!

Step 4: controller, on the right you can see I've placed a sort of daughter board with the controller. I used a dremel'd piece of the original PCB on the left as a standoff

This is how the controller looks from above

The USB connector

This is how it looks now, retr0brighted of course:

Mission accomplished! Level up!