Actually, it's rated well because when fully modified, it still rates as a 200 A-Spec challenge in most rally races. Yes, it turns horribly, accelerates slowly, and is very very heavy, but for A-Spec perfectionists looking for bragging rights, it's a trip!
RE: Skylines. Just did a few comparisons on a lark, between the R34 Skyline and other 98-02 mid-sized to full-sized (1500+ kilogram) cars on N3s at Infineon Sports. While some cars with near 400hp (like the SVT Cobra) can whip it around Infineon, it creams most mid-300hp mid-sized conventional cars from the same era. I'm willing to bet a Lotus or a Porsche can beat it, but I've still to buy a new set of un-oil changed samples (I need to do this to balance it out for secondhand cars).
It understeers, yes, but that's a given for a large car like the Skyline, and not any worse than most big FRs. But it has that awfully neat trick of AWD oversteer that you can't get in the likes of the EVO or WRX. In fact, so far, the one EVO I've gotten close to the Skyline's times is the EVO VII RS, which is 1320 kgs... and then, only
after an oil change to bring its horsepower up to 336 hp (vs 340 hp on the Skyline). The RS version catches up because you can kick the tail end around much more easily than with the GSR and GSR MR versions, which are a bit too grippy on tight corners.
Sure, the Skyline is overpriced, but if you consider its size and its drivetrain, its agility is quite an accomplishment. And remember, AWD cars are comparative slugs in GT4's physics engine, so matching laptimes with an RWD car in any AWD is an accomplishment.
Over-rated? Maybe, maybe not. Over-represented (how many? 50?)? Definitely.