Yes, you could hit with only two fingers on the handle... but the wrist joint would still be exploited. It's bound to happen. It's not a properly speaking a wrist movement as no movement is provoke by a joint. All these movements (supination/pronation; flexion/extension; ulnar/radial deviation) are caused by forearm muscles, but no forehand can be played properly without involving some of these.
One of the major cause for inconsistency in even top pros is often the absence of certain movements and not the pointless presence of hitches. A high performance coach even wrote on his blog that he spent more time adding stuff into good forehands than at suppressing stuff to clean the movements...
Do you know why? Because regardless of how you swing your racket, your string must come at a precise angle and be facing the ground by a fairly well determined bit for your shot to do anything useful at all... you either learn to get your racket there by positioning yourself right when you're moving rather slowly or you learn to change your movement midway through your swing -- the vast majority of pros are doing the second option. Just imagine, they're playing Federer, Nadal, Verdasco, Berdych, Cilic, Djokovic, Tipsarevic, etc., who all present the appropriate preparation, but they can't match their opponents and need to work their movement each time a ball comes... they can't and never will be able to generate nearly as much power as the above on average and they can't rely on the extra control or the extra spin everyone of the above can tap into at will.
How are you supposed to win a match against these athletic phenomenons when they also benefit of an unfair technical edge over the rest of the crowd? The ridicule is that many of these little tweaks could be achieved by amateurs and they could too benefit of a totally unfair edge over their opponents. Your wrist is a cause for mistake ***IF*** you don't position your arm joints properly upfront; if not, that joint and the movements it allows is a source of pace, spin, control and consistency.