>1) The the microswitches go bad after a couple years.

I had this happen to my shop PC mouse's left button. I was too lazy to get another mouse or desolder and put in a new switch, so I tried drilling a small hole in the top of the switch and squirted some Deoxit in there. That fixed it. Later, the right button went bad too, so I did the same thing. Now it's been a year and it's still working.

My speculation: this is due to the lower and lower voltages that “long battery life” wireless mice run.

It’s not necessarily that switches have lowered in quality, it’s that you get less current flow at 1.8V or whatever than 5V and any added resistance exacerbates that.

Maybe adding another pull-up resistor in parallel with the existing one can buy more time per switch.