I think the difference is really pronounced on low bite. There you can see 2WD has a focus on consistent driving coming first, and finding the edge with pushing second. In other words, first you make sure you clear the jumps and don't spin out (that gets you from say an F final to a C final), then you find ways to become quicker (which gets you from a C final to an A final).
In contrast, in 4WD cars will (usually) not have trouble clearing jumps and won't spin out as easily. So much traction begs for an agressive driving style. I've not raced 4WDs more than a few laps, so I can't say how much a difference it makes driving consistently or finding more pace like 2WD (And my view on 4WD may be very much biased as a 2WD driver): I think 4WD puts way less focus on how to clear jumps and drive neatly from the get-go, so people experience it as easier to drive (though the potential power you can unleash may pose the problem of one underestimating the impact of making really clean laps, or when indoors, keeping the car intact)
