Yeah when my phone is on my desk face up it is convenient to need to pick it up of flip it over to unlock it.
Exactly - whichever way you look at it, moving it to the back is a step backwards, as its always going to be more convenient where it is. Having it in the middle, on the back, just isn't a natural position to place a finger when picking the phone up. (For me at least, but I'm sure for a lot of people.)