My 2cts on the hex thing... I've stripped two or three rims max since 1998 on my losi or AE cars... granted, I haven't ran them continuously every season since then, but every time I stripped a rim with the pin, it was clearly because the locknut had come loose... solution is easy, change locknuts often... the hex will help to slow down the stripping phenomenon as it provides more "keying" depth for the axle into the plastic and only one dimension for the rim to move around the "key" (the axial one) but it only slows it down - the solution is new locknuts, regularly

Paul