I hate to include myself within this topic, and promised myself that I wouldn't. I will agree that the .400 pro-tree idea DOES have its special benefits. However, after much conversation with other racers in the comp pits, I have decided to change my mind given their reasons and concerns on the issue.
Racers posed different issues, and some were simple issues, such as figuring out when to get on the two-step with a clutch car, and making appropriate adjustments overall in order to get a decent light on a pro-tree. After discussing it even more, we decided that it just wouldn't work. For the few that it helps, it just isn't worth it due to the fact that it negatively affects many other racers.
I'm all about being fair. Therefore, to be fair on this issue, I would have to say that the idea of a .400 pro-tree WILL be unfair to many racers who oppose it, whether it be for technical or opinionated reasons, it's just unfair.
Have a nice day!