Changing the configuration by raising the gear will result in more drag as the whole wheel well is exposed, equally , raising flaps
that's a lot of interesting things I know nothing about. however in a windshear situation applying max available thrust and focus on flying the aircraft instead of worrying about changing the configuraturation, with possibly minimal benefits sounds like the right thing to do. A and B a/c have very impressive thrust to weight ratios. Whoever is making up their own procedures, against manufacturers recomendations, is probably thinking of some light a/c