The three biggest advances in the last six years or so are:
- COTS frame and gusset options that allow significant customization
- COTS gearboxes that are compact, reliable and provide many options
- The smaller and more robust control system elements, including the RoboRio and motor controllers
Swerve-in-a-box for less than $100/module, requiring nothing other than attachment to standard VF to make a drivebase, would change mobility. I think that's coming.