First off thanks WGT for adding the brackets, nice addition to the game. Sorry if some or all of these ideas have already been posted elsewhere.
Thought of a few things while playing them.
1) Was thinking of a way to speed them up, how about when they reach 4 players, there is a "start early" button and if all 4 (or 2 if its down to that) agree to start early, once the 4th player hits the button the 24 hour timer begins. This could cut down the time by a day or more to wrap it up.
2) Pay out as soon as both players have finished the final round, rather than waiting for the timer to expire. RGs do this in the rare instance that all 50 players do finish the round before the timer expires, they pay out instantly.
3) If you are going to hide a players score on the bracket until the opponent posts theirs, you should also hide it from the score history like you do with RGs. (scores hidden from history until 50 sign up)
4) Don't show who has signed up until all 16 spots are filled. I personally would avoid joining a RG with a cast of all star players, which will make them fill more slowly of course.
Unrelated note, since the rake is 10% in brackets which is spread over a number of rounds, why not lower the rake on RGs to a more reasonable 10% as well? When RGs started in early 2010 the most expensive balls were something like 70 credits, so at that point the rake accounted for maybe half of WGT's take from a RGs when you factor in ball wear. Now with balls costing nearly 10x as much obviously they are generating far more revenue from ball use that from the amount they rake. I feel like more players might be inclined to play RGs if positions 11-15 also showed a small profit, as scores are getting to be ridiculously low. And if more people feel as though they are "winning" credits they're going to be more likely to pull out their wallet for balls which is WGT's bread and butter. So lowering the rake may actually generate more revenue.