I have this problem also, and sorry to be wise after the event but a natural granite will never fade, looks great when power washed and guess what, it is not much more expensive. You would have to look for a supplier, typically a small quarry in a granite area. The large outlets don't do it because they prefer to sell the manufactured product.
Replacing the paving is obviously a big expense, another option is to lift each stone and turn it upside down, the side that is presently on the bottom will not have weathered much if at all.
A lot of work but if you have the time you can probably diy and at least it wont cost anything. You should probably seal it then, no point in sealing the faded stuff.
As for recolouring the existing obviously you could paint it but I dont think that would work very well.