i think in pool rules should keep to a minimum any communication you need to have with your opponent. im serious about this, all it does is cause problems and misunderstandings. the inform your opponent he's on two is a good rule i think, but jerks that you're beating up on take advantage of this stuff by acting like they dont hear you and all the other stuff ive come to expect.
seriously, no call pocket, its just a bad idea.... arguments will go up 100 times. for that reason alone its not worth it.
edit, i just had to add this..... many, many times a player will hit a shot very hard (say a long, difficult shot), miss it, then "luck" it in...... mike sigel is the best at this i think, and he's fooled people too, people think he's lucky. well, i believe that it you weigh things properly in your head, in many situations, hitting hard and missing the ball on accident but then lucking it in can be a great percentage play. "luck" isn't all it's cracked up to be, i suspect the very best players are "lucky" because they are more smart than they are lucky. in other words, we are put in situations on a pool table many times where luck will be one of our greatest allies, and the best percentage players will use this. why take this fascinating aspect out of the game.