Yeah, super hard tires should last at minimum 120 kilometers, but in GT4 they wear out in a matter of 15 laps at fuji, ridiculous.
The super soft kits used to last 3 to 4 laps, c'mon, such sensible and soft tire doesn't really exist, the super soft tires should last 15 laps, not the super hard ones.
Tire brands would be cool, like equipping cars with Pirelli PZero, or Bridgestone Potenza tires, would undoubtly make the car performance stats closer to the real models. I can't see a "Tire war" happening, simply because the tire performance varies from many conditions, and the game won't be able to simulate that properly, like the old Michelin F1 tires, which are less grippy than the Bridgestone tires for the first 5 or 6 laps, after that the tires are warm and the Michelins start to outperform the Bridgestones, things like this won't happen, not in GT5.
A more well-made tire simulation is what we will have, and that's enough for that, tire brands will be only a cosmetic detail IMO.