That's the thing, potential purchasers may well have been put of by the initial internet outrage that gave the impression that the game is rubbish. It may not be the motorsports simulation that many
thought they were going to get but it's still a damn good driving/racing game. It's become my daily driver.
Yes and no. Coming from PC2 I initially thought it was odd, but I've changed my mind.
If you're looking for a full on motorsports recreation, as mentioned above, then the mixed grids can be jarring. But the game isn't that.
If you just want a fun jump in and go racing game then the slightly eclectic grids really aren't so bad. In fact there's a benefit to them. In a grid full of the same type of cars they would have similar performance. The cars in a mixed grid can have varying performance and abilities so give a different challenge. I've had some good battles between slower but manoeuvrable vs faster but more wayward cars.
That said I wish there was a custom car picker to recreate those motorsports moments when you wanted it. But there isn't so I get on with it. The game is what you make of it.