That's fine, but here's the problem. You might never find the stuff you need or only one or two. And they might be useless anyway because they don't provide enough cost reduction. For example, say you find a circlet that reduces Destruction costs by 25%. That's nothing. Last night I didn't realize my characters helmet wasn't on and she began dual casting fireballs at a dragon. I think she got 3 casts off before the magicka ran dry. And that was with
75% reduction costs in place (75%!).
It also severly limits what your character can wear and therefore your armor rating. I did a robes-only mage once and it wasn't any fun because you have to constantly cast flesh protection spells, which eat into your magicka which causes you to have to bring along gads of restore magicka potions so that you can use any of your other spells. Even the Archmage robes did very little to mitigate the problem.
Using Destruction is my favorite way to kill things in Skyrim. But in order to do it consistently I have to have highly enchanted gear. That's just my experience. Everyone's MMV.

We're talking about destruction, so talking about alteration isn't really relevant, you can use armor when using destruction if you want. But I've never had a problem with the flesh spells, I always dual cast them before the fight, giving me a good 4 mins of protection (I wait for my magicka to regenerate before fighting).
I'm not defending destruction, the mechanics for it are terrible, I just know how to make it good enough for use on master. For the higher tier spells you have to have a good 80%+ reduction, 72% and the perk is good enough if you have a decent magicka pool. The items for a cloth mage that have fortify destruction, robes of master, peerless ring and peerless circlet aren't that rare, the Solitude shop will likely stock at least one at high levels.
You can also be a necromage vampire, boosting the enchantments by x1.25, so you can easily get 90+% reduction if you want, this isn't needed though, but my mages are usually necromage vampires depending on their morals as it boosts pretty much everything mages use. I'd never have more than 95% though, that's to much.
UM... NO, it does not. An icicle does 25 damage at 0 skill as it does at 100 skill...
If it isnt obvious that we are talking about --damage-- rather than an obscure concept of magic power (in your mind) then you need to read about fifty threads on this exact topic, just search destruction on the forums.
This is such a non-point, the expert level spells have twice the base damage of a daedric warhammer. The skill is for cost reduction, the spells damage is already high, remember the game needs to be balanced for adept, not master.
Melee just has ways to make it overpowered even on master, destruction doesn't have this luxury. I don't play with overpowered melee characters, so my destruction is usually stronger than melee.
My current character uses both 1h and destruction, and they are both pretty equal, probably destro comes out on top as I have high reduction and a decent magicka pool, so I can pump out 105 damage incinerates (necrovamp) at a very high rate of fire.