OK...I'm totally shooting' from the hip here and haven't put more than 5 seconds into this thought.
What if Stock (not Super Stock) no longer had a minimum index? Maybe on the slower half of the field, maybe the entire field. Still a dial-in format and still a heads-up format where applicable. Still the NHRA blueprint application. Still the same rules. That way a guy that buys a 1987 Camaro or Mustang could actually race it with minimal cash outlay. He can go rounds and be happy. He will no doubt loose on a heads-up run. But at least he can play the game a little and hopefully is encouraged to spend some money to make the car competitive.
Personally, I had always dreamed of having a Stocker and the dream was always dead once I realized how much it took to make a car run under the index, even a marginal amount. But then I bought a daily driver '87 Shelby Daytona Z that was .400 under with spinning street tires. Sure it was a soft index but it was the car that got me in the game. I then set a record and was hooked. I built an engine and set another record along with many #1 qualifier's. I never would have got serious about this had I not had a door that was easy to walk into.
The only problem I see is AHFS. I think that can be resolved with assigning an ET that trips the trigger instead of tripping the trigger off of a baseline index. Let's say today we have a index of 12.50 and the AHFS trigger is 1.00 under. Just make the AHFS trigger an ET or 11.50.