I think for a lot of wizards (practitioners in general) a more defensive stance at the beginning might be appropriate. Hide, block, dodge, then just hit once and do it big. Harry makes a reference to doing something similar in one of the sidebars. I'm a little concerned with the mental state of a person who tends to spend the vast majority of their time and energy aiming at doing harm rather than preventing it, especially when magic is involved.
I agree, defense is appropriate. But consider your options (as action rather than reaction), a wizard can 1) attack, 2) block (including armor), 3) counterspell, or 4) create one or more maneuvers. The maneuver created aspects can be used for either defense or offense. Granted, only once and at a 3:2 ratio instead of 1:1, but the flexibility may well be worth it. It can save your @$$ or be used to wipe the floor with the bad guy...whichever you need more.
Mechanically, stacking aspects is optimal. Creating taggable can also be one of the more group-friendly actions anyone can do...and since you can tag them yourself if no one else does, there's not much downside.
Wizards are mighty when prepared, and they spend a lot of time and energy getting prepared.
Evocators are pretty awesome even when not prepared.