Posted this on the General Discussions equivalent of this thread but..
..according to the guys, Francis Dean's AHT compares the sustained turn characteristics of US fighters in this order, with the smaller number indicating a better turner;
FM-2 100
P-63 124
P-61 133
F6F-5 137
P-51D 179
P-38L 205
P-47D 206
F4U-1D 212
If AHT can be considered a reliable source, looks like sustained turns are about as effective as a P-47D with a P-38L.
Maybe the new FM implies that you shouldn't start a turn fight in the first place with a plane that turns like a P-47. It could be that the AH1 P-38L was actually overmodelled than it is supposed to be at low speed scissors/turn fighting.
In AH2, it is still one of the easiest planes to smoothly transcend into low speeds by use of flaps and rudder. In fact, all of the US planes with effective flap use, is at an advantage when entering into that speed regime, compared to other planes which has to drop speed under 200 and then start deploying flaps.
Maybe it's just after the low-speed status is hit, the P-38 isn't as easy as it used to be in handling? It could be only a perceptual disadvantage which in the case of other planes, suffers even more harshly than the P-38. I know the 109 does handle more bitc*y whenever I have to get it to deplot flaps..