In career mode, being able to see a list of the current other car Manufacturers (Ai), and the cars they are producing, would help make it feel as if your company is competing with something more than just numbers.
The simplest version of this would just be a list of manufacturers, and each year you could see what they are currently selling. This would give you a concrete list of vehicles to beat. Maybe you can’t be #1 but you can beat the number 2 seller by looking as what they do badly. Importantly, would make it very clear what categories have well established competition.
More advanced expansions of this gameplay could have you ‘buying’ their cars, to see how they manage to get the stats that they have. Reverse engineering and such. Could spend tech points specifically on Reverse Engineering, and it could give a bonus to the engineering you are already doing (like a 1.x multiplier or something)
Further (maybe too far):
Investing in ‘spies’ to see what vehicles are currently being designed/built, before they are sold. This would allow you to get the jump on them. The report could have inaccuracies, or maybe even misinformation if the ‘spy’ was compromised.
Knowing how fast their cars run on the test track could be fun, could be a selling point for sports cars, like the Nurburgring became.
Buying/Selling parts and tech to/from other manufacturers. Maybe you make great suspension, so other manufacturers offer to buy the platform from you, or you need a higher output engine, so you order some from the competition. (I’m thinking simplified Supra collaboration)
Or really extreme, buying the other manufacturers to one extent or another Like Ford and Aston Martin, Jaguar, Mazda (not really sure how these work in the real world, but could be a simplified version in the game)
All this is to say, I really like career mode, and hope it keeps getting expanded upon.