That walking punch (or its equivalent in various styles) is probably the simplest moving repetitive drill - can't imagine much simpler. I've drilled equivalents from boxing, Karate, etc.After have tried many different punching drills (I don't want to try kicking drill), The following drill is still the easiest one for me. It's as simple as "step in and punch".
Will someone be able to come up a drill that's easier than this?