Thank you for the answer. from the video, I see the DCT should very comfortable, but I don't think it answer my first question. I did not see any machinery that can make master and slave clutch plates rotate synchronized. the video show the DCT and how it works, two clutch one for odd gear and the other for even gear, the master plate connect to crankshaft, the slave plate connect to output shaft. the gear 3 and gear 2(or 4) has different speed ratio, the slave plate of disengaged clutch should rotate in different speed than slave plate of engaged clutch. but the two master plate should synchronized, so the disengaged clutch should wear.
but I do trust the fact that DCT bikes in forum over 80,000 miles with no clutch pack problems, may be the wear is not as serious as I think.
the problem of DCT is, the rider did not know when it will shift, it would shift down even in manual mode, it sometimes would be a serious problem. motorcycle is a power sensitive machine, the push weight ratio is very big than car. I think this is the main problem, lot of people does not like the feel of lose control.