flying (and building) RC-helicopters, I know small autopilots which are able to help in far more difficult maneuvers than a swim stroke and are able to give back control to neutral in any moment. Well it's leaving the swim
With limited computational resources and the need to work on the least common denominator in terms of stroke mechanics, I think the manufacturers are doing a pretty good job. They're not lazy, stupid, or greedy; the required low power technology simply isn't available yet at a price anyone but the military would want to pay.
Give it 10 or 15 more years and the chips implanted into your forearms, powered by your movement, will provide all that data live on your contact lense display while you're swimming. :)
10-15years... If you become aged, you'll find not enough patience for so long. And when I read all the complaints about the Garmin's and Poolmate's software in processing the whatch's datas... That
are problems which could be fixed easyly. (No confidence to the manufactures in that point.) But as above, it doesn't encourage the thread as it was meant...