What you see in Skyrim is the weakest magic has ever been in a TES game. Even with its faults, I would have to say that Skyrim is the most "balanced", in general, out of the entire series -- there were so many exploits with the previous titles. Custom spells literally let you have your way with the games... I remember making a fly spell and hovering above foes who could not touch me as I blasted them to smithereens from a distance with custom Destro spells -- it was crazy.
@Joe But about Skyrim... you're right... Destruction cannot hold its own anymore, and cannot be relied upon as a major skill -- it is now a support skill to bolster Conjuration or Illusion. Woe to he who thinks he can Destro his way to glory in Skyrim -- especially on master difficulty.
-Loth
Edit: this is the litmus test: Can you play a viable mage without Conjuration/Illusion? Can you play a viable mage without Destruction? Which would you rather not use?
Morrowind was extremely unbalanced, mages had to sleep to regain magic, but with fortify intelligence potions you become an god.
Melee was strong as you could do 6x sneak atack with two-hands weapons, archery was much like Skyrim destruction, to low damage at high levels (blood moon and tribunal)
Enchanting was very powerful but you needed borderland exploits to make your own gear.
Oblivion was much more balanced, all classes suffered from low base damage and enemies with lots of health at high level, destruction was most powerful as you could make spells who stacked weaknesses, they was expensive to cast but gave mages an clear edge.
You could also make enchanted items with stacking weakness however they run out of charges fast making them backup weapon for an archer or mage or an boss killer.
Skyrim turn this upside down, the crafting make weapon users very powerful while destruction has limited possibility to boost damage, not surprising with no spell making.
An mod who rearrange how spell damage is calculated or just some new expert to master spells will solve this.
Think Fallout 3 mini nuke but with larger range and rate of fire and you have a good master level destruction spell.