First bit of bracket racing I participated in was at Lions Dragstrip.

They called it index racing I believe.

The basics were, if you were running a car turning 14.11 or so you entered the 14 second class.
Running 13.99 was a breakout and you lost.
Running a 15.0 was a breakout in the other direction and you lost.

It took care of the sandbagging situation quite well.
I only ran it a few times, but every time, late in the afternoon the cool sea air would roll in and you'd break out on the fast end.

It's not fair to have a car running 9.90's compete in the 12 second bracket class.
All he has to do is get a good start, stay with the racer in the other lane and drive around him whenever he wanted.
Saw that more than few times at the March Meet.

It is a tough question to answer, bracket racing has been good for drag racing, but perhaps it doesn't belong at the national events.

My feelings are, toss bracket racing entirely and bring in idex racing.
One of the things that make it fun is you can take your Ford coupe and run it against a Corvette and see how you do.
The mismatch in car types running a particular index class makes for some reasonably interesting racing for the spectator and a whole lot of fun for the drivers.

Let's face it, not many of us are able to compete in C/Gas and run on the record due to financial constraints for most, but building an index racer that runs high 10's isn't too difficult to do....