Sacred Haven of Debauchery

I have some awesome gear that reduces magic resistance, but the problem is that I use magic from all schools in battle (summon some creature, cast a buff on myself, cast a couple of lightning spells, turn invisible, and heal). And such gear usually only works for one type of magic. Well, I can one-shot giants with a bow from stealth, starting around level 30. It usually takes me more than two arrows only for dragons, and even then, not all of them. But I want to be able to one-shot everyone. I don't even have light armor upgraded, even though I wear it constantly. Simply because I take everyone down with a single arrow.