To be honest I think that this tax may actually be the right thing, but it does not encourage EV ownership. We bought the Bolt to offset as many of our miles as we can, and have been putting about 2k miles a month on it. The Bolt will still save us over $2k a year and we have been kicking around a PHEV for her in a year. All in all this move will allow us to spend $2-3k a year elswhere, the Bolt is really our "gateway drug".
Having an offset for the gas tax is not a bad idea. The problem is the implementation. Instead of rewarding efficiency and pollution reduction, the current implementation penalizes it. IMHO it's a political bent based on the though that EV people are a Tesla type crowd, and therefore can afford to pony up. But not paying any type of road use tax isn't sustainable either. I'm in Georgia, which also has the $200 registration fee for EVs.
I propose using the efficiency, mileage, and current gas tax to formulate an equivalent value for the gas tax paid. For baseline numbers consider 25,000 miles of annual usage, the Bolt's 119 MPGe, and I'll use Georgia's current combined 44 cents state/federal gas tax. The equivalent is simple to compute. The equivalent gallons of gas would be 25000/119 = 210 gallons equivalent. The tax on that is $92.40. Note that it's less than half of the current registration fee.
Now the 25,000 miles was an arbitrary number. For drivers who are willing to put in some legwork, the charge can be reduced by producing a certified actual mileage on the car. It seems that a notarized affadavid showing the actual annual mileage should be enough. So if the car were actually driven 12,500 miles then with the affadavid, the fee would be halved to $46.20.
Note that electricity is already charged sales tax. So the actual funds collection over the year would be more. But something like this would be much more fair than the current system and would only require the production of a chart with fixed mileage for those who don't want to take the time to get their mileage certified.