I agree that the sourdough rack takes away a little of the random nature which makes the break interesting . One of the great moments in 9-ball is when you pocket the 9 on the break. Why else is it called a golden break? With the rack taking this randomness away, the possibility of geting the 9 on the break is either erased completely or, should someone find a way to pocket it once, he can do it every time. I think this is also the reason why they rack the rest of the balls in random, save for the 1-ball and the 9-ball. To keep things from getting boring and monotonous.
Take bowling, for example. They have almost taken away all the randomness from the game. If someone ever invent a robot arm that can roll a bowling ball consistently (the technology for this already exists), it'll get a strike every time. Why? Because it won't get fatigued, wouldn't be distracted, won't get the jitters, etc. The only random event remaining in the game would come probably from the oil and pockmarks on the lane.
A successful pool-playing robot would be decades away since there is still a lot of randomness left in the game. It would be difficult to beat (like the pool simulations in computer games) but it would still be beatable like Deep Blue is to chess.