The problem with the Man-Gets-Hair formula is that every such episode must end in, well, Man-Loses-Hair --- or else the writers would have to come up with something to replace the bald jokes. From the beginning, viewers know the tragic fate of Homer's hair (and subsequent business success), and as a result, the episode loses the spontaneity and potential for the unexpected that usually characterizes the show.
Rather than include a subplot, the episode focuses solely on Homer's story, which is one without much humor. Homer's joyous hair-inspired romp through town is cute, as is his duet with Marge at the end, but there are few, if any, laugh-out-loud jokes. Of course, Harvey Fierstein's character (Karl) provides the one truly great moment of the episode (you'll know it when you see it!) However, Karl is inserted so abruptly into the plotline that I honestly expected him to reveal at the end that he was Homer's guardian angel (and that his real name was Deus Ex Machina.) If the writing for an episode is poor enough to overshadow a performance by Harvey Fierstein, something must be wrong.
In true Simpsons fashion, I give this episode a resounding "meh."