MiracleOfSound said:
So without enchanting/smithing exploits... let's hear some good advice for those who want to focus on Destruction!
Let me just clarify: do you consider any use of Enchanting to be exploiting? If yes, then that's your problem. However, if you consider regular use of Enchanting acceptable, then just enchant a few pieces of armor with pure Destruction enchants (not the ones that also have Magicka regen). With 3 such enchants (maxed enchanting with the perk for better skill enchants, of course) and the Archmage robe, you're around 90% cheaper Destruction spells. With 4 such items you are now at 100% reduction.
As for Destro itself, did you get Impact? Lower spell cost Perks? Damage perks? Destruction actually requires fairly few Perks - Double casting, Impact, Shock Damage (I use Shock spells since they work on almost EVERYTHING) X 2 and any cost reduction perks you deem necessary. And skip the Master level perk, the Master level destro spells suck.
Don't just spam your biggest spell. It can be quite inefficient, especially if you don't have the gear to back it up. Regular old Lightining is quite decent, even at higher levels. Granted, once you have a good amount of cost reduction you can just spam Thunderbolt in peace.
As for your argument that "Surely a primary combat skill should be powerful enough in and of itself to manage the game...", the answer is no, it should not. Can One-handed manage the game alone? Or does it need help from Light/Heavy Armor, Block, Sneak, Smithing, etc.
Also, did you level Conjuration? Summon Dremora Lord is freaking awesome since it scales in the same way enemies do. With 100 Conjuration and the double summon perk you can have two of these bad boys running around while you support with your Destruction spells.
To sum up, I did the following on my Mage:
100 Enchanting -> 3 pieces of gear with Destruction and Conjuration enchants (double enchant Perk)
100 Conjuration -> Double Dremoras, the cost of casting them is low thanks to my enchanted gear
70+ Destruction -> Low cost thanks to my gear, Impact lets me stunlock enemies indefinitely
Your problem is that you think you should be able to handle anything with just one skill, when most character types use a combination of offensive and defensive skills to handle enemies. You assassin needs Sneak to get close and get the big crits, Onehanded for his weapons, Light Armor to keep him alive. Don't be suprised if you can't just "Destro LOLOLOL!" your way through the game...