Enough Cars, More Innovation
Also, what I liked in GT4 was the ability to step away from the actual driving of the car and letting the computer control it with a map display. This is real nice for the endurance races. Or a B-Spec type mode for endurance races would be good. I mean, seriously, sitting in front of a tv going around a track nonstop for 4 hours is ridiculous.
Another feature I would like to see added to the next game to give it depth would be realistic crashes caused from hitting a wall or an opponent. Of course, the option to turn it off would be necessary for beginners, but I think with all the fans out there this would just add to the realism of a simulator. Plus, just seeing a car engine catch on fire and smoking, or a car flipping through the air (similar to Burnout) would just be cool, even for beginners.
To add what I don't like... I recently purchased the updated version of gt5 with the extra cars, and I'm really not a fan, actually extremely disappointed, that they're trying to suck every little penny out of u with being able to play the full game. Point is I paid a pretty hefty price to get the new cars and I expect to have them ready to go when I'm playing it. This marketing strategy to get customers to buy the game then have to go online to buy the cars is bull, and gives the makers a bad name just like dealerships are notorious for their marketing scams. If it continues to mislead buyers in the amount of content they're actually getting, then I, personally, won't buy it.
Lastly, being able to race with recreational vehicles would, at least, be a different addition to the already out-dated simulator. Cruisers, Sport Bikes, Four-wheelers, etc... But as it may be out-dated, it's still the most realistic racing game out there. My congrats.