[spoiler=Return for Base Max (spell) formulas]
Return for Base Max (Pre)
(1 + Special Upgrades) * (1 + Magic Damage) * (1 + Mastery Modifiers + MATK) * 1.1
Return for Base Max (Post)
(1 + Mastery Modifiers) * [[(MATK * Co-efficient) + Base Damage] / Base Damage][/spoiler]
Let's substitute 29% magic damage, +8 matk prefix title, 10 magic attack from enchants, s5, r1 all masteries/spells, no reforges, and the respective elemental mastery title.
[spoiler=Return for Spell Max calculation]
Pre (Any Spell) [Red Line]
y = (1 + 0.17) * (1 + 0.29) * (1 + 0.15 + 0.1 + 0.08 + 0.1 + x/2000 ) * 1.1
Post (Ice Spear) [Blue Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 68 + 10 + x/5) * 1.4 + 240)/ 240)
[Image: http://img11.imageshack.us/img11/6309/edjj.png]
Breakeven: 176 Intelligence
Post (Hailstorm) [Green Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 68 + 10 + x/5) * 3.2 + 300)/ 300)
[Image: http://img62.imageshack.us/img62/7282/ro1g.png]
Breakeven: Below 0 Intelligence
Post (Fireball) [Blue Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 68 + 10 + x/5) * 12 + 2400)/ 2400)
[Image: http://i.imgur.com/3IUdQJM.png]
Breakeven: 608 Intelligence
Post (Thunder) [Orange Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 68 + 10 + x/5) * 2.1 + 400)/ 400)
[Image: http://img839.imageshack.us/img839/8233/hl2g.png]
Breakeven: 439 Intelligence[/spoiler]
As you can probably see, pretty much everyone will be better off with magic provided they do not use reforges. So let's throw reforges into the mix: IS max 20 for Ice Spear Pre, Hailstorm max 20 for Hailstorm pre, and Magic Attack 20 for absolutely everything else.
[spoiler=Reforged Return for Spell Max calculation]
Pre (Ice Spear) [Red Line] Note: Used Last modifier to correct for reforge
y = (1 + 0.17) * (1 + 0.29) * (1 + 0.15 + 0.1 + 0.08 + 0.1 + x/2000 ) * 1.1 * 340/240
Pre (Hailstorm) [Red Line] Note: Used Last modifier to correct for reforge
y = (1 + 0.17) * (1 + 0.29) * (1 + 0.15 + 0.1 + 0.08 + 0.1 + x/2000 ) * 1.1 * 500/300
Pre (Fireball, Thunder) [Red Line]
y = (1 + 0.17) * (1 + 0.29) * (1 + 0.15 + 0.1 + 0.08 + 0.1 + 0.2 + x/2000 ) * 1.1
Post (Ice Spear) [Blue Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 80+ 68 + 10 + x/5) * 1.4 + 240)/ 240)
[Image: http://i.imgur.com/UuTSMos.png]
Breakeven: 1829 Intelligence
Post (Hailstorm) [Green Line]
y = (1 + 0.15 + 0.1) * (((29 + 80 + 32 + 68 + 10 + x/5) * 3.2 + 300)/ 300)
[Image: http://i.imgur.com/FydipRi.png]
Breakeven: Below 0 Intelligence
Post (Fireball) [Purple Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 68 + 10 + x/5) * 12 + 2400)/ 2400)
[Image: http://img89.imageshack.us/img89/1483/6xfs.png]
Breakeven: 208 Intelligence
Post (Thunder) [Orange Line]
y = (1 + 0.15 + 0.1) * (((29 + 32 + 80 + 68 + 10 + x/5) * 2.1 + 400)/ 400)
[Image: http://i.imgur.com/XTb3ys3.png]
Breakeven: 39 Intelligence
[/spoiler]
So what can we take from this? Almost everything will be weaker with low intelligence, but it's rather easy to breakeven and you will slowly start to do more and more damage as you gain intelligence. At cap, this generally involves about a 15~20% damage increase for Thunder, a 12~15% damage increase for fireball, a whopping 35%+ damage increase for hailstorm, and a slight damage
nerf for Ice Spear due to the reforge being gimped. You should be able to push the damage even further than you would now with elemental mastery reforges as well as rosemary gloves since they no longer compound singularly with magic attack.