[EricH]

Originally Posted by AmoryG

Actually pretty much all of my designs require 5 or less motors. One for each ball and one to change the direction all of the balls spin.

I think that's what we call a crab drive.

I think the main reason that ball drives aren't more popular is that there are swerve, crab, omni, and mecanum drives to choose from, some of which are simpler and some of which are more complex to plan and easier to build.