What I gather from this last page is alot of people like cars that don't have rear grip... at all.

The very first thing I have to do to any car's default setup in rFactor 2 is softening up the rear springs, softening up the rear dampers, locking the coast diff, dropping the rear, ... Just to get some wiff of rear grip. But I'm not taking this is as "omg this is exciting, must be real" but rather as "omg, another car with an awfull default setup".
AC is the complete opposite in that aspect (just as Netkar Pro was). Every cars default setup is more or less setup to be understeery so you don't want to shoot yourself when you cant get around T1 for the 5th time in a row because you're not tip toe ing it around as if the track was covered in a layer of ice mixed with oil.
Maybe RF2 is more rear-gripless than it should be, i'm not saying it's perfect. However, in RF2 and the other top sims, I can attribute extremely dynamic and complex car balance, tyre grip slides and microslides, that are extremely dynamically & sensitively affected by how each of us uses our pedals and steering inputs, to real-life, much much more than in AC. This extreme & super highly dynamic complexity (even though it might not be perfectly accurate, and maybe even odd at times) is what it really boils down to in the end for me.
Maybe AC behaves safer and more naturally when you are pushing, let's say 70-85%, but all the top sims I've tried, including Kunos' previous title Netkar Pro, have much more variability and dependency on the user's controls and how much they affect the vehicle dynamics (especially when being driven hard). The physics become a little bland (too much like a "video game" ) for me in AC. It goes much further than just "there is less oversteer so it must not be good", it's the general feeling of how all the cars slip and slide when you're in a slip-angle area of the tyres. It feels a little boring, and you get away with too much, things feel too...I don't know....basic.
For guys who have no racing experience, no theoretical knowledge of weight transfer, car balance, proper techniques, etc. etc. it's just so straightforward and simplistic in the slip angle/limit area for them to just pick up the game and get very good times, good consistency from corner to corner, lap to lap, etc. ("video-game" physics trait). The physics don't have that depth/fidelity/complexity to vary the cars' state of grip and driving dynamics in so many tiny, and not so tiny, ways depending on your control inputs, techniques, skills, how you feel and anticipate the car dynamics at work depending on all the tiny differences between your control inputs, etc. etc.
It seems almost scripted or something, just undynamic. It's like when you go from a PC sim to a console sim, everything just feels so cut down, simplistic and less complex and fidelic going to the console one. Now find a middle ground between that console experience and PC sims, it's right in that middle in-between area where I find AC's handling dynamics. Maybe they are better at feeling natural and under control than other sims, but at the heart of it all when really racing the car, there seems to be this layer of un-complex, much too forgiving, not taking enough things into account regarding how your tiny differences in control inputs can change the car's handling from lap to lap, corner to corner, ease and "basicness" to it all.
For example: In real life I can get 2 EXTREMELY different reactions from a car on, let's say, initial turn-in until about one-third - halfway to the apex. The car balance (when reaching tyre limits/some sort of slip state) and how the car is moving/sliding around underneath you can vary DRASTICALLY depending on the exact precise timing & detailed technique of how the steering is applied (and pedal movements). I can replicate this super complex part of vehicle dynamics and extreme physics complexity depending on your exact precise tiny control input differences, in every sim (including Kunos' previous title), except AC. In AC it's much more just simply "turn the wheel in any generic way you want with no attention to detail, with no drastic changes on handling dynamics based on the exact precise techniques used". It's just so generic and straightforward/linear in it's handling model. It allows so much generic driving skills and techniques to make no difference to the car.
When you are driving a car hard on the slip-angle, you open up a whole new can of worms with regards to how crazy your little tiny inputs can make a difference between spinning, looking like you are glued, fighting the car looking like you are on a knife edge, or looking like you can take a coffee break as it looks so easy. It's almost like a new can of physics laws opens up when you're really driving on those slip angles/limits, BUT NOT IN AC. Instead of this "seemingly new can of physics laws" opening up once you are driving on the slip angle, the opposite happens In AC, the physics become bland, "dead", "linear", and "video-gamish", albeit a realistic, fun and immersive video game that I really like as a product

, just not as a "tool" for real life racing replacement/training.