It's possible you're missing something, but it's hard to find out without a description of how you think the rules work. It's doable for a wizard to get 11 Drain resist dice, which gives them 0.32 post-resist Drain on average for a spell with a Drain Value of 3 - which is what a Force 6 Acid Stream, with a base damage value of 6P and AP -6, will get you. A little higher on the rank, you've got a Force 6 Ball Lightning for an average of 1.5 post-resist Drain, while doing 6P/-6 Electric damage (so -5 to Initiative Score and -1 to all actions for a round unless they reduce the damage to 0) to everyone within a 12-meter diameter circle. And of course, if things get nasty and you've got someone ready to drag you away, you can throw a 12P/-12 Ball Lightning that'll hit everyone within a 24-meter diameter circle.