I think when you start considering the removal of entire classes of motorsport that it's a slippery slope.
I think project cars has always been somewhat more of a racing simulator than a driving simulator, and that's where the focus should lie. I am all for unifying/simplifying the classes a little more in the next game. I really would like a greater variety of available cars in each class that would have raced together in period, whether that be current GT cars to Vintage Formula cars. I guess to that end, if there absolutely had to, then I'd personally sacrifice a few outlier cars to boost the variety of class cars. Stuff like the Ford Raptor and Bronco, just doesn't seem to fit in the game to me.
But if there is a 4x4 audience that they feel they need to target, then why not introduce something like the Super Truck Series from Australia. All of a sudden, an outlier car style that gets lumped in with the rest of the messy road car classes has a true purpose of being in the game, on a race track, and they've hit a complete new target audience.
So yeah, I guess it's efficiency along with the quantity of the car list that I'm after in the next game.