I'm sure we've all been there.. you are riding at night, wearing gloves, and the backlight has gone off so you prod the device to bring it back on. On the map screen this works ok (assuming you are wearing the 'right' kind of gloves) because the zoom/pan overlay doesn't obscure any significant aspect of the screen - so the screen is effectively lit with one tap. However, if you are on a data screen, a single tap just brings up the 'home' overlay which obscures the data beneath it - meaning you have to tap it again to actually see that data.
Now, tapping it twice wouldn't be big issue if the screen worked reliably with gloves - but it's often it's a battle to get one tap recognised, other times the second tap will register twice and you are back to square one.
Maybe I'm the only one - but I can't think of a reason why you'd want to make it more difficult to simply see your data than to return to the homepage when you are in the middle of an activity (particularly given Garmin seem to have made it as difficult as possible to get back to the home screen from other areas!). Shouldn't it be one tap to bring the light on, and a second to bring up the home overlay instead (I think previous Edges worked like that)?