Flames, Sparks and Frostbite only get better by perks and before those perks can be chosen (30), you can get the Apprentice perk (25). The damage bonus from going to the Apprentice spells with the 50% reduced magicka cost is better then the extra 25% bonus you can get from all 3 of the other perks put together as a low leveled mage character.
The wolf can be improved by perks too but again just like the novice level destruction spells, you might as well go Apprentice and summon Flame Atrontch(sp) which is far stronger and has long ranged attacks which do more damage then the familiar is capable of.
Illusion spells are level based and using fury on level 6 mobs is a joke, later on illusion spells can all be increased by 10 levels, but you'll likely be higher then level 16 when you get that particular perk and so will need to use higher leveled spells instead. Also fury is unpredictable, it just makes the target attack the closest thing to it, if that's you then it'll just continue to attack you anyway.
The Damage Spells got way better at level 30 by Perks and Enchantements.
Only 1/6 the cost and X1.5 the damage with X4 the Magicka Pool vs enemys with around (If 2/3 of their ups went into Health) X3 the Health.
I still use them sometimes when there are fast moving enemys like Ice Wraith or Wisps.
Its tedious using them on Master but my guess would be that they are still okay on Adept at level 30.
Lightning Bolt for example is better when it hits, but it is also better then Thunderbolt, so...
Edit: Forgot to add Destruction Dualcasting.
I dont really know about Fury, but shouldnt it affect higher leveled opponents by Dualcasting it ? Wasnt Illusion Dual Casting = more Powerfull ? Iam not sure what it did exactly.
By the time you get the +level Perks it is useless if you didnt went into Illusion heavily.
It simply gets replaced, thats right.