In an interview with Time, Dennis Miller gives this take on the current Weekend Update team:

Tina Fey might be the best "Weekend Update" anchor who ever did it. She writes the funniest jokes. Jimmy Fallon's forte is the sketches. He's got the pre-emptively disheveled haircut. There's too much artifice happening there.

Of course when Dennis Miller was doing Update, and had disheveled hair, that was the style, right? But it's true, Jimmy Fallon has been sporting the bedhead (Josh Hartnett called and he wants his coif back) for a little too long.