I know that tracking strokes, laps and swim distance is much harder than steps. But it's doable because Apple mostly gets it right. Yet nobody beside Apple seems to have nailed the simple pool lap count algorithm (remember some prefer to flip turn while others prefer to turn above water especially at the shallow end) but the iWatch is so crap in so many other ways that the world really needs a competent swim tracker that doesn't need to be on a charger every 20 minutes.

EDIT: Better yet, make it fully open with access to gyro/accel data so I can develop my own perfect, swimmer's app and maybe make some money as an added benefit.