SAS
I dont blame you, but you obviously haven't done too much short strip bush work have you? Don't knock it until you've tried it.
Think about it too instead of firing all guns at once.
Asymetric flap is pretty uncommon, not that it would pose as much of a problem as during a go around.
The pitching moment is almost unnoticable bacuase you are on the ground before it has time to show, but it would help actually, you are raising the nose further, further increasing AOA and drag.
Remeber when you first learnt to fly that, the aircraft will stall at a higher speed with flaps up, this serves to reason that if you want to stop the thing from flying and not come off the ground again (due to wind gusts, bumps in the strip) than getting rid of the flap is going to have that wing stalled sooner rather than later. Again I stress that because of the reduced lift, there is more weight on the mains giving you better breaking.
Just so you are aware, I'm getting rid of the flap just prior to the wheels touching the ground. I only do this when I need to (short bush strips, heavy loads).
Remember you can get float when you dont want it from gusts of wind too, not just because your speed is too high.
Where I work, your attitude would kill people. I suggest if your are competent enough with your 172 than you try a few experiements with retracting the flap after and just before landing and see what happens.
BTW for short field technique, I use 60kts and 55 short final (in certain consditions).
1M