Actually, modern cars can be setup to handle real worldd bumps very well, though this will necessitate the use of multirate springs (i.e use of one stiffer and one softer spring for progressive spring rates) This is absolutely necessary for decent grip and traction and avoid uncessary skipping and crashing and turning races into a complete mess. Another parameter also required and currently unsimulated too is the 4-way damper, which is standard in many modern race cars. The current linear dmpers will only cause skipping and unnecessary crashing and again, generate a complete mess.
The truth is, some of the "fast" setups I see floating around will absolutely bounce the car off your average potholes. Excess softening of linear susupension components only end up with seasick wallowing handling, definitely bad for racing. Try getting a setup for the RB4 for blackwood Rallycross. To survive bumps, you either end up too stiff to avoid ridiculously tall setups or too soft and wallowy setups. This goes a long way to explaining why modern rallycars with decent handling always use multi spring coilovers.
I agree that LFS is currently ironed smooth on all the Tarmac tracks. But to force in realistic bumps (aka BIG AND NASTY) with no mechanism to cope well while generating decent racing speeds safely will only turn LFS into a crashfest.
If you miss the bumps, please run the neglected rallycross circuits (especially blackwood rallycross) and try running through those massive series of bumps without suspension damage without slowing down.