One of the proposed revamps coming in Mists of Pandaria is the way intellect and spirit interact with each other in regards to healers. For the new healer, understanding the current formula for mana regen can be a little daunting. To make it really easy, let's just say that it plays off both your spirit and your intellect. However, your intellect has a gradually increasing impact on how much mana you gain back in combat situations as your gear improves.
It appears that will no longer be the case heading into the next expansion. Ghostcrawler (lead systems designer) helped shed some light on the issue in a blue post earlier in the week.
- Intellect becomes a sheer throughput stat
- Spirit controls the rate of mana regen
- Mana pools will remain fixed