Greg - your points are well taken. personally, I think our engine allowances are fine as they are pretty clear in what IS and IS NOT allowed. but you are right that newer cars are a lot more complicated, and racing is no longer even possible in many cases without substantial investment to rid them of their street-based computer systems. in the old days, you could pull AC and various interior bits, bolt on a header and go have fun. now, as you have learned, you pretty much have to replace the ECU and get it sorted out. some care are lucky to have OBDII tuners available that allow you to change calibrations and deactivate features, but even those are largely older. so the easy to build cars are going to be "old" cars, and parts availability are going to limit which are viable.
we'll continue to class new cars, because in reality the cost of the ECU and all that is a cost of running in front in IT in any car with electronic injection. by the time a full-tilt racecar is built, the cost of the street car you started with is a pretty small portion of the cost, even on much newer cars.
the "problem" is that IT became popular and the cost to run up front got higher. there are certainly winners and losers in the ITCS though - just no way to balance all those cars under our generic rules with basically small weight adjustments and 5 classes to cover ~40 years of automotive innovation.
but yes, we can take a less hard lined stance on things like improved components, even allowing some more better than stock aftermarket components - and we don't try to forbid those improved OEM parts, we just try to maintain spec lines that minimize "needed" mix and match and rare parts, and could result in cars that are too unlike those sold in this country. allowing better than stock aftermarket parts is a VERY slippery slope and could result in more "race" parts rather than "race capable" parts and further raise the bar on track and muddy the line with the Production category.
but LeChump? yeah, there's an attractiveness there, but the cars are just as old as anything in IT.