Couple of very important reasons :
1) While playing one hole on a BB CAN be done and I'll even admit every once in great while can be fun but IMHO playing it on anything smaller than a 4.5x9 really takes away the " essence of the game.
2) As to the " random balls " - as mentioned extremely rare for folks especially pros to pocket " random " balls. Now if you're also talking about intentionally pocketing balls in one of the other 4 pockets...... well I'll say the same thing as above. It's an extremely important part of the game and if that were changed I don't know what you would be playing but it wouldn't be one pocket.
Don't forget the six 2 pocket 1 pocket tables Diamond made ( supposedly to appease Earl ). We can see how popular they turned out to be .
