lighter doesnt always mean better.
lighter with a flywheel does however means that you accelarate faster and at that same rate your revs would fall as well.
(to me a flywheel that light is great for street racing with curves and corners where you do two feet driving to keep the revs up.
i'm not really into that kind of racing but i'm pretty sure some of the other members here do that or auto cross racing.)
turning off from a stand still would be harder and aluminum(which most of the lighter flywheels are made of) cannot take the wear and tear like steel or its alloys and chromoly.
I always thought the stock flywheel was a little too light, not for me or daily driving, but maybe for others. Decrease the weight of the fly wheel and bucking and surging or poor driveablity and clutch engagement may occur in normal driving, but if you are at full throttle this lets the engine rev up quicker and easier due to the less weight spinning around on the back of the crank. I am still not convinced for durability and daily driving.