I think the issue is that not only would you need to be a professional to build one, but that the rules aren't immediately clear what qualifies as a walker. It does seem strange that Pilgrim using a Jansen walker linkage and Spiderbot using a Klaan walker linkage are classed as walkers everywhere except in combat robotics. Unless we want to continue with having events where all the robots look the same and have the same weaponry (which maybe some people do) we need to encourage builders to do something different and the likelihood is that that would need to come from changing the rules somehow, because the arenas are unlikely to change, and I would say that its best they don't. Particularly with the HWs it seems as if an optimum design has been achieved and now it's just a case of copying and changing the paint colour.