I like the idea of leaving the +mana bonus alone and giving it +mana regen instead. Generals need a good +mana regen item. They're always taking Blood because there aren't any other good choices (except for cloak in a few cases).
Not sure if it's possible, but it might be nice to add maybe a 5% or 10% skill resistance to it. Mages don't need armor, after all, they need magic resistance.
There are + mana favor items.
There are early + mana shop items.
There is no need to encroach a new, superior, item in this territory.
eg: What you gain early game, you pay for late game with lower regen rates.
eg: With a 1600 mana staff, do you take vlemish for subpar regen vs a blood of the fallen, 2 helm build? Or do you take Plenor for an incredible mana pool, and spam skills, that will eventually run out. Hoping to send the enemy running before you are vulnerable to his regenerating mana to use another skill shortly. If you manage to get Hungarlings, you are reaping the reward for your choice and skill.
I am seeing that this idea seems to have merrit. There is a bonus, a penalty, a new play style and proper balance to a favor item category that is one of the worst. Those are Large early mana pool, low mana regen, Mana to Life lane control, and mana pool only item.
Now, as for, is it the right amount? Could be too high, could be too low. I can predict arguments for both depending on play style, level of skill & experience and demigod.
