Additionally (nothing wrong with the posts so far):
With low-engine-location craft such as the 737, TOGA thrust with approach flaps still deployed can lead to strong pitch-ups, with possible stalls and/or other loss of control.
Such as this recent event still being discussed, and a couple of others in Russia that were fatal.
http://www.pprune.org/rumours-news/6...8-krr-vko.html
Thus getting the flaps up a bit is a higher safety priority than the gear.