I've been playing pCars since day one, I have around 600 hours of game time across both titles and here is the things I would add/change/improve to make pCars 3 the best of Race-sims.
1- Bug Fixes: First of all fixing the existing problems like the Shadow Glitch/Flicker we get across all tracks, cars and times of day, it really messes with your immersion when that happens. Also the Clutch flicker still happens and also the Wet Track Flicker also happens. So TLDR: fix the graphical and input glitches present in the game engine.
2- AI Adjusts: The AI in this game can either be 1993 Ayrton Senna or a blind man on way too much cocaine, take for example the Red Bull Ring, the AI trough corners 4 to 7 is crazy fast, like they are on rails and they have 300 more HP than you, but in La Sarthe they will crawl between the Dunlop bridge and Tertre Rouge, it makes no sense and if starts to rain, you can win races going on reverse (believe me a managed to do it). Another problem the AI has is dealing with lapping back-markers and being lapped, they either dither all over the track to let the other car trough (sometimes putting 4 wheels on the grass) or they just don't move at all and the other car just nails them in the back at full throttle, add the possibility of AI mechanical failures. TLDR: Revamp the AI, at this point is primitive compared to other sims.
3- Content: Project CARS have a pretty good amount of content, several tracks and most of the relevant cars that people are looking to race, but is always nice to improve your roster. Sebring, Suzuka, Interlagos, Jerez and Silverstone 2009Ver. are some of the tracks that could be added since they are favorites in rival Sims.
As for cars/categories we could have the additions of Formula-E, DTM, V8 Supercars, Japanese Super-GT, WRC, Group B Rally, Drift, to name a few.
4- Gameplay: Apart of the AI changes necessary that were mentioned above, please add more slots for AI opponents in some tracks, Le Mans and Spa with 32 cars, Nurburgring with 30 cars is just plain sad. In game I raced these circuits in 24 hours races, and I would not see a single opponent for hours in some cases. It takes away from the challenges and magic of endurance racing, I'm not saying to put 100 cars on the Nurburgring but aspire to put a option for your players to race against 60ish cars (pCars 1 Le mans had the option to race with 50 opponents, so the tech for it does exist in your Workflow already). The addition of the possibility to create custom championships.
5- Modding: One of the major factors that rFactor and Asseto Corsa are such juggernauts in the market is because of the modding community, they make their games not feel old, Support for mods would be your major weapon. But since I still think Mod support is a far dream for pCars, at least allow people to have more than 1 custom liveries for each car and allow us to pick the opponent cars and liveries during a custom race/champioship.
6- Pyshics: One of the biggest downsides of pCars in my opinion specially on the topic of feedback to the player, improvements in the FFB for wheels is a must. Also a review of physics of the cars is necessary, I had the opportunity to drive some of the cars that are in the game in real life also, and I say that for example that the LaFerrari and Mclaren P1 are completely different in real life is not even close, but some cars are pretty accurate on their physics like the Porsche 911 GT3 R and the Ferrari 488 GTE. So a better study of the real-life references is necessary.
7- Audio: Some adjustments are necessary in this area also, some cars sound way too artificial: Ferrari 488 GT3/GTE, Corvette C7R GTE, Ford GT GTE, Carrera GT. But some cars sound really good and similar to their real counterparts : P1 2016 prototypes, Audi R8 GT3, Porsche 911 RSR GT3, Cayman GT4 to name a few.
8- Graphics: Some additions would be welcome, extra lights on the Endurance classes: Number plate, cockpit interior lights, etc. Also the addition of flag lights and flag marshals around the tracks would add to the immersion. Smoothing of the pit crews also would make the pitstop less... distracting to look at.
9- Extras: Safety Car option, Helmet/Racing Suit customization, Create a Team (carrer mode), Improvements to Photo Mode (GT Sport like), Improvements to Replays, Borderless Mode, Game running on background (annoying to have game stopped every time you alt-Tab, if I want the game to pause I press stop otherwise keep going).
