Ratherbeflying: I think you rather overstate the difference - 1kt min sink from a k13 is on the ambitious side, and I'm pretty sure the 172 doesn't do 8kt down at best glide - not with both wings attached in any case. I'd also argue that 2k is rather high to have picked your field, but that's beside the point.
Realistically there are a multitude of approaches between the idle, full flap glide (steep) and the drag it in over the hedges with the engine working hard against full flap. Surely there's a certain degree of discretion as to what is appropriate for the aeroplane and the circumstances. Being a paranoid type, I tend to err towards the high side on the basis it provides the greater margin of safety. Sure engines rarely fail on short final - but that's little consolation IF it happens to you. I also try to be gentle on the engine. But I'm merely a low hours PPL treading carefully.