Gears only breaking when shifting without clutch.

While clutch failure and nuanced synchro failure would be nice expansions onto the updated system, it absolutely can do what you're talking about already. *As was said above: "The difference between engine speed and wheel speed is what causes that. The bigger, the more damage." Shift as much as you want between gears without clutch while the engine is off and the wheels are stationary. It will not break or damage the gears because the wheel and engine speed are completely matched. If you could use a neutral gear on the controller and actually rev match the engine to the wheels before shifting, you would not damage the gears or would damage them so little that you can still do hundreds of shifts without issue. If you want to test this with a controller still, grab something with long gears and lots of power like the SBR4, get to a speed where you can cruise in 6th gear just above the stall point, and shift down and up repeatedly as fast as you can. It will take many more shifts to damage anything than if you kept jumping between 1st and 2nd without clutching or rev matching because the difference in engine and wheel speed is so much smaller.

If you want to request the devs add a separate clutch button so you can shift the same ways a wheel and shifter can rather than dismissing the objectively more realistic simulation outright, I'm sure both you and they would appreciate the results more. You can also put the car in 1st while the engine is off, hold the gas pedal down, and hold the starter and you will eventually get going without transmission damage or using the clutch already.

*Video Example:


Edit: One thing I would like to ask, is there a way to get gear damage on a debug app currently? It would be nice to have a visual percentage for it just like with the other forms of damage and thermal stress.