Last night, I did the Speaking with Silence quest for the TG. It's the quest where you go with Mercer Frey to Snowveil Sanctum and face all kinds of heavy duty Draugr before meeting Karliah. I was looking forward to this quest because I could actually use area Destruction spells and not have to worry about killing my follower/Frey.
I know that Destruction is weak but I've been trying to make a go of it. So to this end I took along over 30 restore magicka potions, all worth a minimum of 77 points. Most were were 97 points or more. In addition I found 5 or 6 more restore magicka potions along the way. I also carried 6 or 5 fortify magicka potions.Note that this amounts to somewhere in the neighborhood of 4,000 extra magicka points.
I have a necklace that provides an additional 25 points of magicka, a ring with 25, and gauntles with 29. My gilded Elven armor provides my character with an 18% reduction cost in Destruction casting as well as a bonus for regeneration. I also have over 400 magicka before those enhancements, which gives me 500+ total.
I was out of potions about 1/4 of the way through the final fight. After getting killed for the umpteenth time because the controller only gets the dual casting move right about half the time I had to do the unthinkable: turn down the difficulty. I even resorted to scrolls---Scrolls!!
In sum we're looking at 4 solid enhancements and close to 50 restore/regenerate potions and it still wasn't enough. Not even close.
This character does carry a sword which is only to be used in emergencies. Her 1H score is 27 with no perks, but her power attacks caused almost as much damage per hit than my Fireball spells. My Destruction score is 58 and I have every possible perk in the tree at this point.
The only mitigating thing about this is that my armor rating is only around 200. So what I'll do is go to work on that and begin taking more perks. But I think the above is a good anecdotal example of why Destruction is one of the main things Beth may want to adjust with a patch in the future. They adjusted Smithing so I don't see any reason why they can't do it with Destruction.

