I wouldn't recommend 5 Intellect, 2 Rec. But, there is a way to pull this off effectively. Ask yourself these questions and if they are all yes. Then, it might be effective to do so.
Am I just using Base statistics (if yes then 7 Intellect is better)
Am I just using Level 1,2,3 Lapis? (if yes then 7 Intellect is better)
Am I running Dread armor with Level 3 and 4 Rec lapis or better in them? (if yes, then 5 Intellect, 2 Rec would be effective from around levels 30-somewhere in the high 40's).
Am I running all Defensive Dual Lapis in Dreads or better? (if yes, then 5 Intellect, 2 Rec will work from levels 30-the high 40's. After that, your defense will still be beneficial. But, its main role will be to lower the amount of damage you are taking to your mage.
Once you hit Pando with your Mage. The game changes completely. With no Wisdom per level. You will need to fill your Dreads. With all Dual Wisdoms lapis and/or level 4 or better. All four slots in your dreads for your Boots, Gloves, Pants, Armor and Weapon. Will have to be filled with these lapis. Your 2 Rec per level will become completely useless at this point and it will actually increase the chances that your character will die. Because you will have higher aggro to your character.
You could fill your characters Dreads full of Wisdom and Rec lapis. Even doing this will not help you. You still will not have enough accuracy from your Wisdom. To hit at a relieable rate. Which is what you need for aoe. Your defense will also only lower the amount of damage to your character. Basically, you will not be any good as a mage.
Overall, I say 7 Intellect per level is the way to go. It will get you from level 1-your high 40's faster than any other build. 5 Intellect, 2 Wisdom is another way to go. It will make managing your higher levels much easier. You can lapis all Wisdom and Rec Duals to this build. To make your character an effective aoe later on. You should never add Wisdom to a Mage/Priest for the purpose of increasing mana though. It will not benefit you in the least and it will actually play against you.
If you are a casual player (7 Intellect is by far the best build for you). If you get to the end game. Then you will have to restat but it will be worth it.
If you are a Regular or Intermediate player (5 Intellect, 2 Wisdom is a solid option). Not recommended for the casual player. As you will just slow down your grinding if you aren't established enough to lapis 4's or higher to everything.