First, on a general note: the Wizard's more useful while he lasts because, frankly, the Modular Ability guy doesn't have huge Specialty and Foci bonuses on all his actions like the Wizard. Now the Wizard runs out of juice quicker but an 8 to attack with Weapon 8 is a bit better than the max 5 Modular Ability guy can have to attack with what...Weapon 11? Max? If you assume the car still counts as Weapon 5 if thrown? On the other hand, he doesn't last forever, he'll run out of Mental Stress after a while. I'm not saying a Wizard is flat-out better than the Modular Ability guy, just on par.
There is a difference between tagging a car aspect to make your spell have a cool special effect, and treating a car like a freaking paperweight.
In terms of how useful it is? Not really.
Yes, the wizard is about as useful as the modular abilities guy in that situation. But the modular abilities guy can change what he is good at in a moments notice, and the wizard can't.
See above, as long as his Mental Stress lasts, he's good at everything he can justify with magic. And Spirit justifies a whole lot.
And how the heck do you get 8 control and power in all spirit evocations for the level of refresh we are talking about?
Simple:
Superb Conviction and Discipline.
Evocation [-3]
Thaumaturgy [-3]
Refinement [-2]
The Sight [-1]-Note: The guy in question has Marked By Power, I figure this is in the same category of uselessness.
Evocation Specializations: Elements (Air, Water, Spirit); Power (Spirit +1), Control (Spirit +2)
Focus Items:
Shield Glove [+2 Defensive Power, +1 Defensive Control for Spirit]
Striking Glove [+2 Offensive Power, +1 Offensive Control for Spirit]
He's a specialist, but not at all inappropriate as a PC (assuming a good background, anyway).