Pickin´ arps especially over all strings demands lots control and it´s damn hard to play fast but somtimes it´s easyer than to sweep ´em. A sweep is much much faster but I would like to see a guy who can sweep slowly and yet tight. That´s where alternate pickin´ with perhaps some modificiation (economy, slide, pulls and hammers) come in picture at least for me. Crossroads is a great example.