I was a fan of GT until GT4. it was a huge disappointment.
Things I want to see, or issues address. With the assumption technical glitches are IRONED out.
1. Online Play supporting at least 6 human/player cars, NO MORE than 8. too many cars per race will slow servers, bandwidth and not be practical.
2. 500 legit cars would be nice. from 1950's up.
3. TEST online play before releasing.
4. Improve the physics engine even more.
5. record real engine sounds. i.e. as someone mentioned earlier, for all instance and purpose, if i have a 3500 lb skyline, and the only thing I do is lighten it 2 times. and it theoretically loses 400 lbs, it should shave noticeable time off the car around a track, or in the quarter mile.
6. Improve graphics immensly.Youve got the storage medium-and youve got the processing power.
7. Bring back some of the old GT tracks.
8. Make almost all driving options adjustable- even on/off is good for some.
9. Make sure tire changes show the cars attitude changes. i.e. summer tires in winter climates have no traction. I've witnessed this personally(unfortunately). And All-season tires dont compare to 2 laps on heated summer tires. i.e. Michelin MX4 vs. Michelin Pilot Sport 2..... PS2s will outshine the MX4 any day of the week. (ive driven on them both)
10. Allow garage cars to race online. this is crucial.
11. Money should NOT be a factor in online play- it does NOT belong in this game. General tournaments are fine.
12. Do not make online play $20 a month. I would be willing to support $10/month provided SONY/Microsoft can promise 98% uptime on servers and NO lag. Service Level Agreements anyone? Hence why I said no more than 8 cars/players per race.
13. Buy, or in some intelligent way, work out Porsche, Ferrari and Lamborghini. I grew up studying these cars, even been in a few. May never own one, I'd like to race one

, get them. Period. RUF is legally a manufacturer, as they are now world recognized as one. But I still want some other porsches.
14. Online villages. i.e. simple chat room, and meeting place to scedule races. I do not want video chat, no online music center, no picture sharing. The reason, when companies, and I am addressing almost all of them, ATTEMPT to implement too many features, they LOSE sight of the GOAL of the product. FOCUS on game play, reliability and graphics and sound. All I want to do as far as GT5 is concerned is turn on my PS3, select online play, initiate whatever game is in there, and choose a function- such as race players, chat in a room, the rooms should be one per state, or town, and rooms according to that, i.e. New York- Setup Race 1, Setup Race 2, Setup Race 3, Chat 1, Chat 2, Chat 3.......again, we dont need pictures, we dont need music. just simple , Effective performance.
15. Make sure weather effects, effect cars as they do in the real world. in rain, soaked streets, drifting is much easier, and hammering the thottle is a BAD thing. I.e. When launching, I dont know one Gran Touring series, Nascar, or F1 that allows a FLOORED gas pedal to take off stable and sooner than a steady application of gas. Which brings me to the next thing.
16. Make control more precise, yet fun and accurate. If the controller is analog in nature, make sure the range of motion is used. give buttons and levers range of motion enough to allow the smooth operation of a car. too often it does not mimic real life. I know its a game, but its also supposed to be fun.
17. Allow night driving, with real headlight usage.
18. Punish drivers for veering off course, cost them speed, punish drivers who hit others with a loss in speed, i.e. -15 mph, and maybe 3 seconds. This should go to the initiator. If both cars were on the same vector, give them BOTH the penalty.
19. Allow the proper drifting setup. for cars. i.e. front and rear tire grip choices.
20. Provide Dolby Digital 5.1 Audio. I want to know if a guy in a Volkswagon .:R32 is creeping on my Ferrari F430. I want to hear his tires and engine from the right rear and make a move to prevent it. Also, ive dropped enough dough in sound equipment, and Id like to use it. hear that PD/Sony?
-------------thats all for now. just adding my piece-----------