You gave up a shield for more damage, now you complain you don't have enough defense... you can't give defensive perks like that to dual wield, it'd make 1h+shield entirely pointless. It'd be like asking for damage health spells in the alteration school, they don't belong there. Also people with 2H can still block if you hadn't noticed, I mean what are you expecting to parry and with what? There is no realistic way a 1 handed sword or a dagger could parry a warhammer and they'd have a hard time parrying a mace or an axe, the only thing you could really parry is another sword or dagger which would dramatically weaken swords...
as for a "dodge option", that's called you walking around. If you get enough sneak then you can get the roll perk, 10% evasion is the pinnacle of light armor.
I didn't "give up" a shield, the character I'm playing is an assassin, he happens to not have proficiency with shields. I played a 1h + shield on my last playthrough and it was actually really easy, I think even if Dual-Wield had a semi-reliable parry move or a dodge mechanic similar to Quick Reflexes, 1h + shield would still be superior. (And about damage spells in alteration, I was actually hoping we'd be able to move people with telekinesis to throw or push them around

, but unfortunately it's just a minor spell to move small objects again.)
Now, a block with a dagger or a one-handed weapon wouldn't be as strong as a 2H or shield block, so have us time parries to block other light weapons and have larger weapons knock you back or go through the block at least partially. Parrying with a dagger actually had it's own fighting style after all, main-gauche, which uses the dagger primarily for defense against light weaponry. Would it be effective against a 2H weapon? No, but it shouldn't be, it should go right through and make you rethink your tactics for fighting against heavier weapons. But you would be able to parry some weapons, just not as well as you would have if you were a shield proficient character.
Maybe Deft movement (not liking the passive damage avoidance aspect though, not in an active form of combat) and the stealth roll help out some though, I'll keep at it and see for myself I guess.