Also, let's not forget Maurice Hurley, who was essentially the showrunner during season two of TNG. Roddenberry was still actively involved in the show at that point, but had cut back his day-to-day involvement, and Piller had not yet come on board. Berman and Hurley were the two people running the day-to-day operations during that season, with Hurley being the one focused on the creative/writing side.
In fact, despite popular perception, Hurley was Berman's equal during those early years, whereas Piller always reported to Berman. You'll note that both Hurley and Berman share the same title in the opening credits and, in fact, if you pay attention you'll note that each episode alternates who's credit is displayed first and who's is second, so as to give them truly equal billing.