The PS3 has all kinds of power for implementing this kind of stuff, such as Amar's wear system, along with Scaff's incidental damage, for maybe 24 cars at a time. This may be what Kazunori-dono is shooting for, and we'll see.
Most people don't mind not seeing cars damaged. To them it's just a quirk. I don't remember anyone complaining that Enthusia doesn't have damage, and as usual with GT, it's the same 20 some odd people harping that realistic damage HAS to be there. Frankly, I'm happy with whatever. Going back to GT4, it's odd not being able to hurt the cars any, but I'm not disappointed.
However, damage does make a game more "grown up." To many people, Forza's partial damage system is good enough. To a certain degree more or less, Toca's damage system is good enough. Basic but fairly comprehensive. Some want sim-level damage like GTR. Amar's concept has been kicked around somewhat. Most don't take well to it, but it depends on how it's implemented.
I would enjoy a system where your car did wear over time, and the harder you were on your car, the more you'd have to spend to tend to wear issues. Oil changes, tire budget, brake wear, tranny issues, maybe clutch fade. And then there's chassis damage from collisions, assuming it wasn't too severe. This kind of thing would be fine with me, as long as it was manageable. If I got overwhelmed with costs or the tedium of having to scroll through a list of issues, I wouldn't want that. GTR has such detail that the radiator cap pressure can be adjusted, and that's just too much for me. That's why drivers have a crew chief and mechanics. Just give me the repair bill, itemized or not. An itemized system would be good, because your crew chief can go over why certain faults happened. "Too hard on the brakes, so they and the tires wear out too soon." This would encourage you to race properly, and would matter a great deal on endurance races.
What I wouldn't want to see is something so realistic that the game would randomly kill my car. A tire blowout, causing a DNF. If I was Sega Rally powersliding everywhere, that would be one thing. But playing Russian roulette? Not my idea of fun to have a race end early just because the game threw in a random critical roll.
Detailed settings for a damage/wear system would almost be necessary, but this would give Kaz and the lads plenty of freedom to go as deep as they wanted to. The player could have the damage system they could handle. But I have to wonder how many of us would go all the way to where the game could end a race on a whim.