Fines are effective. Governments are going to do something with the money. Picking a price curve that closely matches actual cost of running the department seems better than what we do now. Yes, officers will have a preference for pulling over a ferarri instead of some beat up old honda, but with all of the automation the article talked about, it seems like the times an officer has a choice between the two are rare. If the policy is pull over everyone breaking the law, officers would have to account for not pulling over cheap cars.
Now, i could see a good argument for simply requiring public service from everyone. The thing we're all limited by is time. 10 hours of a rich guy's time is just as valuable as 10 hours of a poor guy's time (to them at least). Of course, you're not really proposing this as an alternative, you appear to be saying because it's not perfect, it's not worth doing.