So I have had a few ideas which are really small and fine, but it is the smaller details which i notice and feel need to be in the game if it is meant to be a simulation game (which it is).
So firstly is the gravel. In real life, gravel is there to slow you down once you go off, some are deeper than others, but the majority of them are deep enough that you cant get out of them once you hit them. The only way is by keeping your speed up and driving through it.
Gravel is a 'killer' for your car, it gets everywhere and sometimes does more damage to the car then if you had just 'nudged' the wall instead. So the whole point of a simulation game is to make it as realistic as possible. At the moment, the gravel effects do nothing different to the grass when you hit them. There should be a distinct difference between the two. Both grass and gravel react differently in wet conditions, so this is something we also need to look into, as we do not want the same in all conditions as this is unrealistic.
So in terms of sound, when you go off into the gravel, it is quite loud and you know you have hit the gravel trap because of how the car sometimes just 'digs' into the stones and gets stuck, this is where the term 'beached' comes from as it just lifts the wheels off the floor and the bottom of the car just sinks in. The biggest thing you notice once you leave the gravel is how much is left in the car, so inside the bumpers etc. It takes a good 2 or 3 laps for the gravel to fall out and clear, so before that happens, you hear gravel just moving around from side to side when you go through corners. It is like having a bag of gravel emptied into the boot of your road car and it is just moving around everywhere. So these sounds need to be added to the game to add this affect to the gravel. When the gravel starts falling out throughout the lap, it starts falling out onto the tyres and the racing line etc, so this sometimes causes a change in grip level when you turn in.
This is just my idea that i think should be added in, so the sound of the gravel in the car and falling out onto the circuit, the change in grip level sometimes as the gravel falls out. This should be noticeable with the graphics so you can see the stones falling from the car onto the track, and lastly the affect of the gravel when you hit it should be increased, so can get 'beached' etc.
Obviously some gamers want to just play the game and not get punished for their mistakes if they go off, for me, if you want it to be realistic, then getting punished when you make a mistake and go off where you may be out of the race is what is needed. As in real life it punishes you a lot, and that is what makes the difference between the real world and the virtual world of motorsport. Either way, there could be the option to turn off the realistic effects of the gravel for the gamers who just want to have fun without taking it seriously.
Lastly, dust and dirt being carried back onto the track from other people going off should be added as this is a very important thing. One lap, you may have plenty of grip through a corner, but the next lap a driver who has gone off could have brought a load of dirt onto the circuit which changes the grip levels completely, this can even happen when you are following a car closely from behind. When they are pushing, they may drop a wheel in the dirt and drag it back onto the circuit, which then affects you who is behind them.
Just a few ideas