Which include the fact that you can't improve magic anyhow through enchanting (not true, just not in the way you do with melee damage), and that meleeing a troll with a greatsword is the same thing as casting spells on him.
Sadly, damage isn't everything you need to account for when balancing abilities. And this is what makes the "you can use all your tools, not just Destruction spells" argument sound.
You can't directly compare the damage of a melee swing and a spell and call it a day. A spell hits from range, often with additional effect. It can deal sustained damage. It can stagged. It can slow. It can enable kiting. It often requires less time than cocking and releasing an arrow. Also, warriors don't get more swings over time, and stamina doesn't increase at the same rate as magicka. The cost and frequency at which you can use spells IS an increase in effectiveness.
A smart Destruction mage will start damaging its target well before a two-hander wielding barbarian engages in melee. He will have tools to stagger his target before it gets to him, he has tools to disengage if things go hairy. He can slow the target. He can freeze it.
He can kill it before it gets to him, while the warrior is forced to trade blows. He can damage multiple targets at the same time, something only a two-hander expert can and at worse conditions. He can single out targets and crowd control the rest.
And I'm not even mentioning evocations or conjuration. Now, imagine if said mage was dealing the same damage per second the warrior is, on top of all of that. The advantage of range, of exploiting elemental weaknesses, of staggering/slowing/freezing/stopping enemies, on top of the same damage.
Now, of course, you may say "I have no interests in those tools, I want to be a pure damage mage". Ok, fine, but if Bethesda gave you what you want, a smarter mage than you will use all his tool AND enjoy the increased damage, and that would be overpowered.
The only way to balance out a mage dealing as much damage per second as a damage oriented warrior would be that of locking said damage abilities at the end of multiple perk trees that don't allow the Destruction mage to get anything else and anyone else to take said perks. It's impossible.
It's really not a complex argument, guys. A sword is a sword, and does only one thing. Damage. Magic has dozens of different advantages over that, on top of unmatched flexibility. You can't ask for the same damage with a straight face.



