As anyone else who has played IV on PC can attest, (which is somewhat spoiling I guess) its so much better having the ability to adjust these parameters. You can alter these for cops as well to make it more balanced. That is why I love PC gaming, as long as developers will remain mod-friendly. You can set up cars for as close to realistic speed/acceleration/deceleration, suspension, COG adjustments etc., you can set them up for drifting, whatever your pleasure.
Personally, I dont expect R* to rework everything to please every gamer, you wont ever do that because THAT is unrealistic as ppl's driving preferences are different - hence the option to adjust them yourself being given at least somewhat of a realistic baseline. There are some very obvious things that they can fix, like HellsKilla mentioned that "brick effect." Its not only that they seem heavier but more powerful than your vehicle.
I recall an incident I had w/ a taxi, we're positioned bumper to bumper (speaking realistically), he has a 4-6Klb taxi, I'm in about an 8-10Klb old truck. He somehow manages to push my truck backwards whilst I'm holding the brake or giving it full throttle, not likely...
True enough this game isnt specifically a "driving simulator" where we choose from transmission and drive-axle ratios based on best E.T. goals, choosing from diff materials for flywheels to reduce weight, adjusting fuel-to-air ratios for the best mpg and/or horsepower. We arent selecting internal engine components for stroking engines to produce more power for circle-track or straight-line drag racing etc. I dont see anyone asking for these kinds of things, just that when a vehicle of lesser weight doesnt behave like it weighs 10tons and your 10ton vehicle is as if it weighs as little as a tumbleweed. Also cops should not have a *light-speed button* as an OEM feature either! They could fix things like this to provide a better balance overall.