Yet a no time did they think to include GPS in the watch or make it waterproof, i.e. make it a useful sports watch that you can use away from your iPhone. Ah...
The Apple Watch was designed to serve as both a wrist-mounted extension to your iPhone as well as a fitness tracker - all while looking good rather than like some dorky geek toy, and with battery power to last all day.
Adding GPS would have likely killed the all day battery life, or would have required a larger case to accommodate a larger battery.
Making it more water resistant would have required a case designed with gaskets and o-rings around the display, the digital crown, the friends button, the speaker and microphone, and perhaps also the case back containing biometric sensors. Again, this would have made the watch bigger.
A watch without a day's worth of battery power or so bulky that it resembled an Android product would have failed. Good design is all about focusing on the most important goals and making difficult choices.