Great post, giving us a nice trip down memory lane, but ....
Corey's soft break was already around by 2000 and was, in the eyes of many, the reason he beat Immonen 11-0 in the 2001 US Open 9ball final.
In 2002, in the wake of a lot of complaining by the players that the soft break had made the game too repetitious (an opinion that I shared at the time), some rules changes were made to outlaw the soft break. As we can see, a new iteration of the soft break had reared its ugly head again by 2007. Perhaps this was a case of either a) the rules changes being made at the BCA level and not the WPA level, or b) poor enforcement of rules already on the books, but I just do not know.
The suggestion that the soft break makes it easier to run the table is false. On average, the soft break leaves more clusters. However, as the result of the soft break is more predictable than that of the hard break, the soft break increases the likelihood that the breaker will be the one that controls the table first after the break, thereby increasing the breaker's win rate.
Matchroom has resolved the breaking issue to my complete satisfaction. Everyone can learn to make the one in the side with nine on the spot and the tight Matchroom break box, but the position after the break is unpredictable, as is evidenced by the 24% B&R rate (per At Large stats) at the recently completed World 9ball.
When it comes to the break, "soft" is a four-letter word.