If I had my way there would be a GT Mode disc and an Arcade mode disc. GT Mode would be all the usual GT goodness minus the standard cars, time trials, used car dealerships and morpheus mode.
I'd sell a Pro Edition that came with LED Covered gloves too so the PS4 camera could track your hands on the steering wheel/flipping the bird to a car your overtaking
GT MODE
The menu needs to be streamlined to a quick navigation system. It'd still be a typical menu layout but with the addition of hotkeys to get around via the use of the shoulder buttons to get to specific areas of the menu. Eg whilst I'm at any sub menu of the game depressing a certain button corresponds to where I get taken L1: Licences, L2: Dealerships, R1: Race Tracks, R2: Garage... or something like that like the original Gran Turismo had
Qualifying is back. It should never have left.
Standing start is back too, but my AI is smart enough that racers wont overtake the entire pack at the first corner.
I like the option during championship series' to skip straight to the beginning of the next race round once you have finished the previous race. None of that Exit; Go to next; Start Next stuff to scroll through if you dont want to.
I'd theme weekends around big race events. October would see something like Group C RX7s, XY Falcons, VL Commodores, Winfield R32s etc under a Bathurst themed update pack.
I'd bring back Driving Missions for these race events too. It'd have to be paid DLC and rather difficult to achieve with proper rewards like genuine racing liveries(that you can never ever bloody purchase), personalized plates and other cosmetics that give absolutely no advantage on the race track.
Missions would be based on real life events like for instance going from 3rd to first in the last lap:
http://www.autosport.com/news/report.php/id/117628
or perhaps re-enacting lap record moments like this:
Lan play this game needs lan play.
Smart phones and PCs could be used to give "team orders" during endurance races. Enduros can be played against AI(AI is actually intelligent this time round rather than being automatically inferiorlike in past GT versions), against others online or for the superior atmosphere against others via LAN.
I'd be all over team racing especially for endurance races. It would need to have some organization so you'd have to register your teams of 3(like registering for a club on Driveclub). Endurance racing would have the option of running the full race live or a resume race mode. Resume race would allow racers from different timezones to be in the same team though obviously resume race would be against AI only. Damage/deteriation would carry over to the next driver just like it would in real life.
Spectating someone else racing would be like sitting at home watching a motor race from fixed cameras along the race track /helicopter shots or hood cam/in car camera. No chase cam etc. Though it would be more intelligent with the ability for the spectator to pull up the monitor view to allow the spectator to study the drivers racing technique, driving lines, throttle/brake work and, if the driver(or in the case of enduros - team) allows it, the spectator can even see what settings the car is using.
ARCADE MODE
Visually this would be a watered down version of GT mode to try achieve a higher locked 120 FPS, less cars on track, no damage, less polys etc and it would have 1 camera view specifically for the morpheus.
Arcade mode will theoretically have more cars than GT, I'd be using all the tracks from past GTs as well.
Standard cars are still in this version of the game because they are apart of what made this game what it is today... j/k I just like having a ton of RX7s.
Time trial is more suited to Arcade Mode, so too are things like Sierra Time Rally. These will have a decent leaderboard setup so you can compare yourself to others in same vehicle/region/date or of course see where you're rated in the world.
You have access to your GT mode garage and there is a free Used Car dealership full of "standards"(though you can not access these cars from GT mode or even see them). Actually its not full, it's dependent on the standard cars you export from GT6. They'll need to have custom parts already installed before exporting since Arcade Mode allows you to adjust your settings on the car to sports specs but Arcade Mode doesn't have a credit system so no point in having a mod shop to buy parts.
Winning races is about winning garage space to house more cars, unlocking more tracks, personalized plates and unlocking paint chips that can also be added to your GT Mode paint chip collection.