Panic/Frenzy etc are useless against single targets, unless you enjoy just sitting there for whatever reason instead of doing anything else to finish it off. Sure, Mayhem or whatever is great against giant/mammoth camps but it's like I said, comedic relief. There's absolutely never a reason to use those spells other than for laughs. Illusion has invisibility if you really have to use it, but the other spells are not worth putting points into the tree for. Unless of course you like slow and tedious.
I disagree, frenzy and the like are very useful for clearing dungeons, they offer crowd control, start a fight with a few bandits, drop a fear on the melee guy to ease some of the pressure off of you, then hit their archer/other melee with frenzy, then go invisible, now they are killing eachother and the first to fall gets reanimated with conjuration, it breaks invisibility but by this point you shouldn't need it, and if you are in a harder fight, throw some illusion buffs on your ally, it isn't a useless school, it is just indirect.
EDIT: and yes single target encounters make frenzy worthless, but fear still does well if they pressure you too hard, not to mention you are a mage, get an ally, buff your armor (yay dragonskin) and fight to win, make use of what is there.