I would like to point out that adding "lol" to the end of your sentence makes you sound like a 10-year-old AOLer. Some people don't mind, but others will assume you're worthless based on only that. I'm normally in the second group, but I'll be nice for now.
I was also somewhat joking about "nerf it now". Mainly I was providing a counterpoint to the original poster, who really is a 10-year-old and can't do anything but pump out units and attack.
That said, either interpretation of "fast" is an incredible advantage, and far more than any other UU I've ever seen. Consider that you use workers the entire game, whereas other UUs are only relevant during a certain age (although I'll admit some of the good players seem to be able to end a game before their UU goes out of style). Also, you always need and use workers, while you may not ever have a need for the certain military unit, or you might not get the right resource in time.
Your idea about them increasing the cost is actually pretty good. If fast means then complete improvements faster, than India just ends up with more compact workers: an India worker costs twice as much but works twice as fast. (They probably won't be twice as fast, though.) If fast instead means movement speed, then an extra 10 shields (50 instead of 40- aren't workers 40 now?) might be a decent enough balancing factor.