Ok, The way is see it is that wizards are so far behind the curve that it is 10/10 for other classes. I don't know how I can make it more clear, if somebody is stood still, clicking medium hp pots, a wizard cannot kill them. Now, obviously nobody ever stands still. So until you up the damage, it's not even something we can compare in terms of who would win. if the opponent has HP pots (everybody carries hp pots) the wizard CANNOT win.
The way is see balance working is, you just aim for the perfect balance, you're never going to do that just by looking at maths, you need to apply it, and see how it affects the game. Right now, the numbers are so far off, we can't even begin the fine tuning process. I don't want wizards FC to do more damage than an archer, I want it to an amount that's a bit less, but still has an impact. that's the idea, a wiz shouldn't beat an archer 1 vs 1. Right now, an archer just laughs and hp pots the damage without any concerns.
Pet's need to stay out of it in my opinion, you need to invest up to an hour to get those, and in pvp, taos can poison them, and they can be killed. this means you have lost an entire hour. It's a bit like comparing someone on a fortitude elixir on LOL vs someone without. You have invested in that short term perk, so it's not something you can compare linearly.
I really think doubling the damage of FC, lightning, and icestorm would be a great start. FC and Icestorm damage is SO low, doubling it might not be enough. 20 dmgx2 is only 40. Lightning will benefit the most from a double, and so it should, that spell has always HURT when hit by it. Once you double these spells damage, you can then begin to tune it. Right now, it's just nowhere near correct, maybe doubling it will be too much, maybe not enough, let's do it and see!?
TL : DR - You cannot begin to balance wizard vs *other class* if the wizard cannot do any damage to them, its 10/10 win for the other class. let's improve this.