Dear GGG: Scaling problems with Mana builds and how to fix them

The scaling for mana builds is a mess after the 0.2 nerfs. Many things deserved nerfs and/or changes, but the current state of mana builds is not good. As such I want to point out a few notable problems that are easy to address.

Eldritch Battery was over nerfed. This keystone was too strong, but double mana costs on top of having no energy shield is too brutal. Having the keystone only cause mana costs to be 50% more instead would leave it in a viable, but not overpowered position.

Mana Regeneration Rate on the skill tree doesn't scale well with player gear at all. The increased regen rate from gear and the skill tree don't multiply off of each other and have heavily noticeable diminishing returns that makes heavy investment feel terrible. This could be smoothly fixed by changing the mana regeneration rate on the skill tree to instead grant percent mana regeneration instead.

Archmage's mana cost scaling on gem level makes it way to rough to transition a build into. The cost should be 6% at all gem levels. Something else like the damage should scale on gem level instead.