Wasn't there a time a while back when the wizard wasn't so powerful? I somewhat remember hearing that he didn't have any problems until he got the tower. The wizard is in the core set and he's been out for a while. They shouldn't change the wizard unless it's really the only way to fix him. If he does get an errata, I think it should be x3 for untrained elemental schools, and nothing else. 3x nature school doesn't make sense thematically. Beastmaster doesn't pay triple for arcane spells and neither does the Druid. Nature is sometimes opposed to technology, but not science. Science asks questions, technology is application of the answers, and sometimes these applications pollute the natural environment. That's probably part of why the Druid pays triple for war spells but not arcane.
The wizard always includes an attack spell toolbox in his spellbooks because it's too good not to. That might be the case even without the tower, but I'm not certain of that. I'd like to see more variety of wizards. There are wizard spellbooks that I haven't or barely seen in a really long time, since people realized how good attack spell toolbox is. In particular I'm thinking of mana denial and teleport pit. Also, the water wizard needs fleshing out. The water wizard's main thing is being able to afford extra acid balls, surging waves and dissolves. Other than that he doesn't really set himself apart much from other wizards, though he has potential. Tbh I think the water wizard's niche should be tanking, but without the battle forge. Dissolve is range 0-1, and he has enchanter's wardstones, and rust.
For instance, summon a gargoyle sentry and a staff of the arcanum, put out a wardstone or two, start enchanting. Obelisk cloak and orb for swarms. Essence drains for bigger creatures. Drain power and powerful water attack spell for finisher (if and when they exist). The problem with this is that battle forge only costs 1 more point for water wizard than fire wizard, fire wizard can do forge tank better than water, and there is currently no incentive for the wizard to go the enchantment tank route over the forge.
Also on another note:
Basic melee attack is a "free" 3 dice attack, and Hawkeye + arcane zap is 4 dice for 4 mana. Having a spell that you can use again and again isn't always OP. Look at force pull.
Also I agree with sharkbait. Dispel should not be novice. That would mess things up even more. Nullify is not used in every book.