Forerunner 235 "always On"

Actually, for watchfaces, they are kind of forced to be "lean and mean". From what I understand, the default watchface basically runs on it's own chip, allowing the main processor to really slow down to save battery.

For Connect IQ watchfaces, they are really restricted in what they can do to conserve battery. (no access to GPS, sensors, no input buttons, etc). Most of the time they run in what CIQ calls "low power mode", where the display only updates once a minute, but with a wrist gesture, drop out of "low power mode", and the display updates every second for about 10 seconds (this is why you can't see seconds all the time on CIQ watchfaces - just when it drops out of low power mode).

Using just the watchface and doing the background step counting, etc, the battery already lasts over a week on many of the devices. Also, the ability to always see the time without actually triggering it by a wrist gesture is probably a feature people like.

Coming from an Apple Watch, I'd take the always on feature any day of the week over the wrist turn. That said, I have ran at night using the wrist turn for backlight. It worked very well. I'm just happy I don't have to charge the 235 every night. That's been a huge plus. I run everything maxed too.

Your anticipated "doubling" of the watch's battery life is infeasible in my opinion. You simply won't get the kind of power savings you think exist.

The actual LCD display, if not changing, uses VERY little power. Remember LCD watches from years ago, the ones that ran for months/years on a tiny little battery? What burns up the battery on most displays you see today is the backlight used to make the color displays vibrant and visible.