After reading through all of this, I think the best solution Ive seen that will help solve some problems, yet keep most happy, is a gatekeeper/knarly obstacle at the begining.
Leave the length/width restrictions out. Build a difficult obsatcle right at the start. Something that an unpreppared driver/rig will not be able to make it up, over, around, or through. Make it tight so its hard for the larger vehicles to fit, and off camber so the open diff rigs have trouble.
This way you are not really shutting out people just for their choice in vehicles, but more for their experience, vehicle capability.
We all know its not really the vehicle size, but more the driver as to what a rig will do on the trail. You see fully capable rigs in the hands of the unexperienced have trouble where a much lesser vehicle with a more experienced driver walks right through.
I would not like to see restrictions of any kind. I am under the proposed length limit with my current vehicle, but the next one will be close. Either way if they enforce the length rule, will they enforce the tire size and lockers next? I sure hope not. My current vehicle is a basically stock 80 Toyota, open front and rear, never had a set of "meats" on it until recently (still just 33s). Just stuck a winch on the front and had fun.
The Busywild has been one of my favorites since I found it, I have had more capable rigs in the past, but, honestly, the busywild is the most fun in this stock toy. Except for a month or two during the winter it is fun yet still challenging. Lock it up front and rear and throw some big tires on it and the challenge goes away, except for a few holes of course.
I still have fun on the trail with the stock toyota even in the raily season where its a mess down there, i dont mind breaking the winch out in a couple of those holes. Using a tree saver of course
Sorry, im rambling, i'll keep quiet now.