The entire topic is about a solution looking for a problem. Despite hundreds of hours spent in FH2, I've seen this exploit used only ONCE. And even then, that ended badly for the user: the Tiger driver zipped his turret around to shoot at an infantryman who was not even an AT guy. Meanwhile, a Crusader appeared in his front and hit him in the suddenly exposed rear turret. Scratch one kittah.
While more sensitivity means that the turret turns faster, for precise aiming you have to tone it down anyway, which takes time (and a keypress) while the non-adjusting user just points and shoots. I find that a constant turret speed is much easier to aim with anyway rather than changing sensitivity back and forth. I do have a variable-sensitivity mouse, and after a couple of rounds of playing I found that I have much more use for two extra buttons (right now mapped for map and map scaling) rather than something which I would rarely need and would not usually be worth the effort. If I HAVE to turn my turret 180 degrees in one second something probably went wrong with my tactics already. And in FH2 vehicle combat, tactics ARE more important than reflexes (or mouse sensitivity). And apparently most FH2 players think along similar lines, otherwise everyone and their dog would be using this "exploit".