we did it, unintentionally on our last trip. for various reasons we arrived just after 3, rather than 2pm.(not much of a difference, but when the park closes at either 5 or 6, i can't remmber which now, but it was early)
lockers were sold out and park was packed, as typhoon lagoon was closed for refurb. so there was just the 1 water partk. but as we were arrivign, there were tonnes of people LEAVING. we were able to get a locker immediately, towels, the lines were minimal. we waited no more than 2 or 3 min max to get on the slides we wanted.there were still a lot of people there, but it was managable and nice. the sky was cloudy, there was more shade, and we were so happy we went at that time.