Until I saw Hawkeye, I used to say the same about McGrath. I mean, I
knew he was brilliant, but watching him, all he ever did was bowl the ball. With people like Vettori and McGrath, it's all about deception. I guess Vettori has deceived you quite effectively.
Knowing where to bowl to each batsman, knowing what fields to set for them, changing your pace, using slightly different balls... anything can work if you do it right. McGrath doesn't need to be as fast as Lee or Bond just like Vettori doesn't need to turn it like Murali or Warne.
EDIT: For what it's worth, I have the same thought of Vettori. It doesn't look like anything until you can actually see the change of pace, or the 'bowling plan' or something of the sorts. Vettori, like Vaas, isn't a "spectacular" bowler in my opinion and looking at his bowling and not knowing who he was, I'd think he was very ordinary if I didn't take the time to find out what he's doing. Of course, you have to rely on other players or the commentators to actually let you know that.