WGTicon - In real life tournaments considered important enough to enforce the "One Ball Rule" players are often put "on the clock". They are not given unlimited time to shoot. Simply put the 90 second clock as the mandatory clock in all WGT tournaments, single player rounds or not. That keeps the game level for all players.
The tournament shot clock could then be expanded to country club tournaments where the tournament "designer" could choose whether to allow twosomes and up with the mandatory 90 second timer. It would really improve the country club experience.
Either immediately or eventually WGT could expand the country club tournament setup options to include the various shot clock lengths. You may see a lot more business as clubs are setting up more and more tournaments with varying shot clocks.
There is no unfair insight on putts and such compared to real life either. In any given round players watch the other players' shot for insight. On some shots my playing partners are watching my shots when I shoot first and on others I'm watching theirs when they shoot first. It evens out over the course of the round.