I already deconstructed this two weeks, so I’ll just quote myself.
. . . That having been said, itemization later in the game balances it out far more than it is currently sitting at, and tying spell damage to intellect would either have to be so minuscule that it’s essentially worthless, or it would be so good that you may as well remove spell damage on gear, as it’d be far more effective at increasing your damage and your mana pool to simply stack int.