The epoxy potting is probably a good part of why it lasted so long. The whole PCB module was only $34 from milwaukee tool, but it's not available anymore. Too old.
I was thinking since it still works at <11.5v I could splice a buck converter in between the battery and the electronics to lower the voltage - then it would work, at least for a while. Or, just keep it for parts. It's 100% mechanically sound, the motor works fine, trigger works fine.
I might also do that router dealybobber soon. If you still care to see it, I'll post some pictures; Looks like I might not actually have to do any real work though. I think the murata connectors are going to work. Not sure if I'm happy or sad about that.