Fire wand = red.
The 415 magic attack break-even for firebolt assumes the player has 0 firebolt damage contribution from max damage as a source, which would only apply to newbies or supercalifragilisticexpialidociously pure mages. Since everyone else has other sources of firebolt damage that don't include magic attack, the break-even point is much much lower.
Staff = blue.
Why?
1. 70% of the reason to use a staff is Lightning Rod. Even if you do extremely inefficient things and get 618 magic attack (without a 10 minute magic weapon power pot) and a red staff, you'll only make blue and red EQUAL in average damage and you would need a number much larger than that for there to even be a noticeable difference.
2. Magic balance is 100%. In other skillsets where balance is capped at 80%, CDMG inherently has more value since critical portions ignore the balance formula. Magic crits and non-crits are more properly balanced.
3. MOST IMPORTANTLY: Most magic skill mechanics revolve around dealing burst damage with slow refire and mass aggro. Getting non-crit fireball to OHKO and save you from any aggro and having to cast again, extra ice spear chaining because you can actually get chains started without having to pray to RNG, etc is far more valuable towards practical DPS.
Higher average damage of red only matters when damage is actually constant and not wasted, but in current content red critical damage for magic is mostly wasted because blue crits are already overkill.