I liked the 2002 version the best: each team had 3 numbers resered for the cars nominated to score manufacturers points that made it very clear who the main crews were. That being said, numbers are less and less important, they are less prominent on the car, not sure how easy they are to see when the car flys past, if the drivers can build a brand with the fixed numbers fine by me.
EDIT: to clarify in 2002 the numbers were 3 in sequence, unlike previous years, so Peugeot had 1-2-3, Ford had 4-5-6 and so on.