On another current thread, I posted the following bullet points for keeping wizards in line:
-Limit thaumaturgy somehow. Either use a homebrew fix or just exercise the GM's right to dictate how long a ritual takes. By the RAW a 200 shift ritual doesn't have to take longer than a 10 shift one, but you can and should change that. You don't even have to change the rules, you just have to use GM discretion the way Evil Hat seems to have assumed people would.
-Don't allow social/mental attacks with evocation, which is sort of a houserule and sort of RAW.
-Pretend Orbius does not exist. Just trust me on this one.
-Keep the weaknesses of wizards in mind. They can only cast a limited number of times per scene, they lack Speed and
Toughness, their skills are tied up in magical stuff. So they tend to have trouble in social scenes, very long fight scenes, and very short fight scenes.
-Encourage other players to optimize a bit. Wizards are sort of optimized by default, as long as they stick to one element and keep their casting skills high. Everything in the template is useful and it all fits well together. So to compete, other PCs should also have decent builds.
It sounds like the first bullet is what you're primarily concerned with, which makes sense because it's probably the most important.
In an ideal world, Thaumaturgy would be no better and no worse than solving your problems with other methods. In the world we live in, it's generally better unless the GM is quick with his fiat.
So you'll want to use that fiat to introduce actual time limitations on thaumaturgy. So that
You can't do a long ritual if the villain is going to blow up the city in two minutes from now.
which was clearly the intention and probably only not in the rules because the writers figured people would work it out for themselves.
Also, talk to your player and say you'd like the focus of the game not to be on rituals. This is not a game balance thing, it's just establishing the desired playstyle up front.
You really don't want to have a player who thinks he's playing Thaumaturgy: The RPG unless you actually are playing that.
(Which might be cool, actually. I'd be up for a game of Thaumaturgy: The RPG, even if I was not playing a wizard.)