I like to subscribe to Ian Chappel's theory. It doesnt matter how you get runs as long as you get them. Aesthicity is fine but I prefer hard runs to looking good. Yuvraj Singh has one of the best cover drives and on drives in the game currently but it means nothing. Cover drives are also played mostly off long hops and overpitched deliveries and essentially is not one of the toughest shots to essay. I think the most difficult shots to play are the front foot pull (Ponting!), the paddle sweep (Tendulkar), the on-drive (Tendulkar).