I totally see your point... Im not saying zero rules for classes. You obviously have to have an organized set of rules to keep everything on an even keel. Something like:
-Drivers under a year of experience
-Under 300hp
-Production vehicle
-Drivers under 3 years of experience
-Under 500hp
-Production vehicle
Then within each one of those as long as those rules are met, you can go wild. If the sanctioning body keeps banning new technology, whats the point of even running new cars? Time and technology keep changing so eventually the tech has to get into the races.
Disclaimer: Obviously my rules for the classes are the most basic ever, but its just to demonstrate the point. Not what I think should be the only rules to a GT3 class.