Who are generally stronger; melee or ranged?

Technically both because Draven.

No one, because generally ranged suck without melee. (they would die before they stack mana/ stack rageblade/ get ranged buff). and vise versa, melee generally wont do enough damage again

melee comp still need mage buff or some carry. and vise versa

Ranged. However, a Friend of mine proved last night that Sorcerer Is stronger than both (Depending how you play it)

I won a #1 on pure Sorcerer last night. Beat Noble, Guns, Demons, etc.

If you can get your mana near full at the beginning of a fight, Sorc has the tools to kill anyone before they are a threat.

If you don't, you'll lose hard.