Although I haven't actually worn one yet, just from the looks I agree. I'm kinda thinking if they can slim down the chips inside, make a slightly thicker battery, then make the sensors on the bottom flush, that would be a good upgrade.
But, until I actually try one one........
If you wear it you'll get a better sense of why the sensors aren't flush. As uncomfortable as it sounds they need to protrude and dig in a little. Don't worry, unless you've got your band too tight you don't really feel it.