I'm all for a policy of players being allowed to say what they want really, as long as it's not racist or something. Who cares if someone tries to 'sledge' another player, just get on with it.
The problem for me is when it turns physical though, or threats of that kind of thing. I don't mind seeing a bit of verbal, but players being pushed and blocked off (on purpose, not the Benn/Johnson thing) I don't think there's a place for in the game.
Oh, and shying at the stumps, if the batsman just stood there, let the bowler do it and just hit the ball back at them as hard as possible, they'd soon stop doing it when the batsman is in his crease.