Our hot start after the AS break had Dunn batting second. He was hitting, we were winning, and getting good pitching. I haven't checked but I think all that changed the very day we moved Dunn out of #2.
I think having a consistent batting order provides an element of stability and generally helps players performance. An occasional change is Ok for specific reasons but should be temporary. Our constant lineup change(except for Jr - who's always third) is disruptive.