maybe i wouldnt label it technically unsound. i was taught both ways to feint. I think there both pretty sound ways.
I say...when you talking technical sound technique,I think Ricardo Lopez...defence,movement,offensive,ranging...to name a few. Floyd is more of a defensive fighter...he works from the backfoot in most of his fights...unless the cat is outgunned for speed...think Corales,Gatti etc...In that way he is very similar to SweetPea..the difference being Whittaker was more offensive...he threw a lot in his prime.... A technically perfect fighter...you would have to take SRR and merge SweetPea...that si the closest you gonna get to being a perfectly technical fighter... Most of the time..for all his natural talent...fights scared(for lack of a better term)....his graet equalizer being his speed....much like Roy Jones..he exception being that at his best,Roy jones had concussive power(if you ignore the showboating)....I'd venture and say Leonard was technically more sound than Floyd in almost every aspect...except denfensively maybe.. Great fighter tho'.
I think Floyd is defensively optimised -- his technique compliments his physical gifts in a way that maximizes output. Depending on your definition, this is or is not 'technically sound'. Floyd utilizes and has come to rely on reflexes, speed and a plethora of other physical gifts, and though the shoulder rolls are impressive, he would have to retool significantly at, say, age 43, because his physical gifts would no longer be there and his style is not technically sound. Offensively, the punches he throws are thrown correctly but I do not believe he has explored all there could have been to him. I do not think he has maximized his potential there and think his technique is tooled around his defense more.
Major offensive flaw: Sometimes FMJ has a tendency to throw (and usually land) one punch, and leave it at that when he could have followed up with something else. The combinations can flow easily, they just don't as often as they could. Major defensive flaw: Does have a tendency to retreat back to the ropes in straight lines, and even if that's an intentional tactic, and even if he's avoiding punches all the while, it can give the judges the impression that he's being bothered by his opponent's defensive out-put. Still, in terms of the aesthetic value of a fighter's technical skill, there are very few fighters who can match FMJ when he's at his best.
I don't think mAyweather controls the mid-distance as well as most other great technicians.The backing up t the ropes often is a sign of that.
I'm not saying I will base it 100% on 1 fight. It seems you took my sentence out of proportion. My point is that Floyd has never faced a great technician. In fact the best technician he's fought might be Oscar de la Hoya who himself relied more on his natural gifts than his technique, and who had lost those natural gifts by the time Floyd fought him. So in terms of Floyd's technical skills, maybe fighting a guy like JMM is what we need to see to make a more complete decision.