I would agree that the rolling boil is more important for AG, for the reasons waldoar said, but I imagine that not getting a good boil going would affect an extract brew as well. I would think the hop utilization would be different. You also mentioned that you wanted to replicate an earlier recipe... since this time you used more water in the boil and had a different process, it probably won't turn out the same. It still may turn out very good, but it will probably be a noticeably different beer from your last one. Are you using a gas or electric stove?