Being a slow swimmer with triathlon background, Your Best Freestyle Technique by Gary Hall Sr was eye-opening to me.
My kick has always been too weak to get really fast with the hip-driven technique, but with a good wetsuit I've been able to swim the 3.8 km in an Ironman comfortably under one hour. I used to prefer a slow stroke rate and two-beat kick because I wanted to save my energy and legs for the bike and the run. The wetsuit sure makes things a lot easier, but there's room for improvement in my swim technique.
I might give the shoulder-driven fast-stroke-rate freestyle swimming a try ands see how it goes. It sure would be cool to get faster in water, but that's not going to be easy. I'd need to get my stroke rate high and be able to keep it up for 3,800 meters.