This is going to be long:
Kaz has stated this game is going to be a combination of every Gran Turismo game that existed before and will be a big step for the future as well.
So what I want is basically a combination of the BEST things of all the Gran Turismo games of the past:
1. Cars
-Obivously... Who didn't see this coming? We are fans of cars, and what made for example the likes of GT2 and GT4 such sucessful games, was the vast number and variety of cars, as well as some of those unique ones that you didn't know about it until you played those games.
So basically, I want variety, a good one, of road cars and racing cars. Especially the later. GTS was so focused on it's own road-turned-racing/rally cars that we as fans just couldn't care less about and wanted more real life racing cars that we are fans of.
The Vision cars for example. It's fine to have them, but IMO they should have their own sub-menu AND their own events. I really, really don't like seeing races with mixture of Group C and/or LMP1 and then these Vision Gr.1 cars in a race track. I don't mind real-life LMP1 + Gr. C cars racing each other, but putting fictional cars in the mix just doesn't cut it for me. What I don't mind being fictional are the tracks, especially good ones like High Speed Ring, Grand Valey and Trial Mountain.
2. Tracks
-Again, everyone saw it coming. However, I am not going to be worried about this because Monza, Suzuka, Fuji, La Sarthe, Nurburgring, Monaco, Laguna Seca and other well known real life circuits (and their own good fictional ones, eg. Trial Mountain) are going to be in the game.
3. Career mode like Gran Turismo 4 and/or Gran Turismo 5.
-License Tests, that are somewhat challenging and are actually meaningfull, that you really need them to do a Special mission or event or even a race. Special events like the Driving Missions Gran Turismo 4 had or the Special Events that Gran Turismo 5 had. The Rally event in GT5 actually wasn't that bad, it was just easy and small, but it was a good step up from previous (and successor) games.
Races of all kinds with the nostalgic FF, FR, MR, Sunday, Clubman cups etc... Throwing into there some Formula Series with 15 races+ like Gran Turismo 4 had with it's FGT event, some NASCAR or some other event of a certain type of vehicle to make it feel unique.
4. Tuning
-We know basic components (engine upg, turbos, etc) tuning is going to return, but I am also expecting a big improvement on skirts, wings, spliters like we had in GT5's GT auto, but on a much larger number of cars. I also have the feel I'm not going to be disappointed with this.
6. Prize cars / money / grinding.
-We want to do GT League events and actually WIN something that they were worth their time and effort. Gran Turismo 4 for 90% of it's events actually gave us very good cars after we completed an event. Not like Gran Turismo 5 where you won totally random cars in big events, like the 24hr of Nurburgring in B-Spec where you won a McLaren MP4-12C that you could've just bought for 200k credits. Or a Catterham Fireblade from winning the FGT championship. Most of those, including from GT6 as well, were just downright insulting.
And then there's grinding methods. They HAVE to change. Prize money from championships and each individual race has to actually be WORTH it, if you are going to include TEN 20 million credit cars. Seasonal events are not an option and giving 2x the money for being online isn't either because those will disappear once Online servers shut down and for those who want to start the game at a later stage or play it again, it will be just horrible.
7. B-Spec.
-Return of B-Spec, with it being a mixture of GT4s and GT5s. NOT having duplicate events (1 for A-Spec and 1 for B-Spec) but to have the B-Spec driver actually drive for us when we get tired, especially in those 24hr long endurance races. But of course, with the ability to raise the ability of our B-Spec driver like we did in GT5. And this also helps with grinding.
8. Difficulty
-I don't want the entire game to be difficult. Not all of us (most actually) have the time to actually be good to do so many super hard challenges or have money to buy a wheel (like doing Diamond in the Hamilton challenges in GTS), but I want there to be exist a couple or so challenges were we actually have to work for them, challenges that makes us grief so much but that after we acomplish them, we feel super satisfied and proud. Again, the Hamilton DLC, the Vettel Red Bull X challenges in GT5, the Mission 34 in GT4, I want a few events that are actually really, really hard to do.
That's what I want, mostly, from this game. Couldn't care less about Online... But if it's like GTS, it's a bonus.
PS: A non-broken PENALTY system is also really a huge requirement.