In a mid-engine, RWD car, more weight is on the rear wheels.
As for why you’d build FR instead of MR in the tycoon: Service Costs. MR is for your super-cars, not your sports car for the general public.
I think the wheel spin is, perhaps, a bit too enthusiastic, but then again, if you plant your foot in, say, a Ford Mustang GT, you’re going to light the rear tires up unless you have traction control. If you plant your foot in a Ford F150, you almost certainly will light the rear tires up. Heck, planting your foot in a Honda Civic can light the front tires up if done aggressively enough, though only for a brief moment.
And for a more aggressive example, look at the Tesla Model S. It’s a vehicle that’s all torque and a good bit of horsepower, and launch videos are all over YouTube, in a car where all you hear is shrieking tires. Yes, it’s electric, but the purpose of torque = wheelspin is more obvious when you’ve got loads of it all in the low end.
Yes, I think there is a mild balance issue, but even still, it’s only mild and this is a game undergoing constant changes.
Oh, and other possible reasons for the MR getting better drivability: Better weight distribution, different suspension tuning, different suspension system, different tires, more aerodynamic, etc. There’s no body in game (yet) that allows both FR and MR mounting of engines to do perfect identical setup testing with just the engine location as the difference.
Essentially, as it currently is, if you’ve got a lot of torque, you will have wheelspin. Trucks are very light in the back, so they’ll have more wheelspin than a sedan or hatchback of similar size. Mid-Rear engine mounting puts more weight on the rear wheels, reducing wheelspin. Countering wheelspin involves wider tires, grippier tread compounds, adjusting the gearing with the Spacing slider and top speed slider, adjusting the rim diameter, and trying to shift the weight balance toward the driving tires.
And as for AWD saying you have no wheelspin, I have several designs that can, and do, carry significant wheelspin penalties. Yes, they’ve got lots of power, but they do spin, even the Mid-AWD has wheelspin. They tend to be more tolerant of it because it’s harder (like in real life) to break all four tires loose for any significant distance. Mid-Rear is used for similar reasons in real life, because of better weight distribution, more weight on the driving wheels, thereby less wheelspin. Front wheel drive gets its own fair share of wheelspin, and that’s in a design with all the weight possible on the driving tires (in the current design of the game, anyway) because of simple weight transfer.
Perhaps the numbers are a little high, maybe they’re a little low, but that’s why it’s early access testing. Plus, we don’t know the exact way the game calculates wheelspin. It could be the equivalent of “I dropped a brick on the gas pedal and counted how long it did a burnout for” all the way to, “This is the upper percentage of the throttle that can’t be used in the first (2, 3, 4) forward gears due to breaking the tires loose.”
And I got ninja’d by Killrob, who pretty much confirmed what I spent the last 4 or 5 minutes typing out. MR has more weight on the drive axle and higher service costs, which will undoubtedly kick it in the butt during Tycoon mode. AWD should cancel a significant amount of wheelspin penalty due to it powering all four wheels at the same time. FR has less weight on the drive axle, lower service costs, and higher wheelspin. Trucks make lots of torque, torque leads to wheelspin. Trucks are light in the back end, being light on the drive axle leads to wheelspin.