FFB is so important for driving feel
Game mechanism is also important too, otherwise no goal, easy to get bored. Interesting setup (you’re the boss of world), story line.
Crash better not too harsh, easy to recover.

Other cars are not necessary in open world.
Rich road types are important. Dirt, asphalt , off road, water.
Realistic graphics are desirable. So beautiful and astonishing.
Open world needs to have a lot of interesting events, otherwise it’s just boring driving around.