Wickard is one of those cases that when you read it, you immediately know that it is wrongly decided, even if you don't know anything about the law. In effect, Wickard found that a private citizen interfered with interstate commerce by growing something he intended for his own use. There is no way that the constitution even remotely suggests that this can ever be the case.
Unless you're a liberal ... or a big-government "conservative" like some on this thread.