I agree with all the points, except for one. If we make unlocking cars much quicker than it is now (just like you want it), you will be able to unlock every single car (D to A class) in matter of 2 weeks, which sucks, because this gamemode is more of an RPG gamemode rather than "~15 hours to complete" system that singleplayer NFS games had. There's a big difference between creating good singleplayer progression and good multiplayer progression. If we make it so you spend 20 hours to unlock all the cars, you will get bored after that and stop playing..
However I do agree that maybe we should make first cars easier to unlock and then higher class cars will be hard to unlock.
However I do agree that maybe we should make first cars easier to unlock and then higher class cars will be hard to unlock.