Maybe I should just leave this one alone...but what the hell?
I actually do agree that the low blow is a much less-used move in the WWE than it used to be. I have noticed in watching classic matches from way back, this move was used more, usually by a smaller heel against a larger face (or a larger heel in a purely competitive sense, although the deliverer of the move was usually a heel.) I agree that it was probably reduced in frequency to avoid complaints.
That being said, I do think that this move is perhaps a little under-utilized. The match between Christian and Mark Henry which happened recently on Smackdown might have befitted from Christian throwing in a low shot to Mark Henry if only for the crowd reaction it would have gotten. Dolph Ziggler is another wrestler I could see making a little more use of this move against someone like The Great Khali. Del Rio throwing in a low blow on Cena in the upcoming Hell in a Cell match might not be a bad idea either.
Yeah, it's only one move, but it always gets a reaction. I do think it should be used judiciously...but I also don't think it's a move that the WWE should be afraid to use a little more.