This was many times discussed on RSC as so as here. I will try to summarize some frequently spoken ideas related to mixture adujstment
M.Adj has some sense only when you have a better modelled engine. Different mixture means different power, different power means different reliability, different reliability means different care about overreving, do I have continue?
This option will lead to uneven car perofrmances.
It is different from car setups. There is no 100% optimal car setup. I give an example.
I 've downloaded Flotch's rallycross setup for XRT because I raced with the default rallycross setup and I thought my bad times are caused by it. But with Flotch's set I just wasn't able to go aroun d the corner. Why? Because that setup just didn't fit me. Different racers preffers different car setups. Clear?
But With engine it's different. If there'll be a grid of GTi's, every GTi has the same 90kW engine and be sure if there'll be an option how to set engite to 92kW, EVERY racer will do it. LFS at the moment doesn't models engine damage is some advanced way, so there'll be no penalty in reliability. So, why do we need to have adjustable value, when we know that every racer with IQ greater than 55 will set to the best value that he'll found on the setupfield?
That's all from me. You'll see that I'm not alone who thinks same. If I have to say the truth, I've also suggested similar idea on RSC half a year ago, but when I tought about it, I realized it has no sense at the moment. Wait for S2, maybe some latter version of S2 with complete damage. Your suggestion isn't bad, but it's simply not feasible actually.