1:15 isn't bad for 2 miles/3 kilometers, especially if it was your first open water race ever. For most people, the first one is all about finishing and getting through it.
By all means do the other strokes and train for pool races. Some of the fastest open water swimmers do both. I've heard of a triathlete/open water swimmer who mainly trains butterfly in the winter. Towards the end of April you start to do long intervals, with or without other people.
Me, I'm sort of semi-competitive. I'd like to do more pool racing, having tried it for the first time last winter, and I aim to do 2 or 3 open water events in the summer. I'm hoping to move up to the 5k distance next season.
But my biggest pleasure so far has just been vacation swimming. Swimtrek tours, or just going out for an hour before breakfast while staying at some out-of-the-way resort, such as in Belize two years ago. Watching the little fish darting under me as I glide along. Seeing startled faces on flotation toys and docks as I swim past and wave to them. Sprinting frantically for shore when some mysterious creature keeps bumping into my legs... okay, forget that one.