I'd like to hear Tyler's response to this.

(this of course, would be weird for pvp)

You would still need mana, but they could change Eclipse to be a different kind of resource instead of the slider-bar that we have now. Unfortunately, I believe most of us have given into the fact that Eclipse will always be clunky.

Blizz seems to like the idea of having a primary resource (like mana) and a seconday resource (combat points for rogues, runes for dks), so they're plan to extend this system to with light/dark orbs for monks and shadow orbs for spriests. This mechanic would even make sense for a boomkin: Having mana as a primary resource, solar and lunar energy would become two secondary resources. Here's what monks could teach us:

For example, Starfire would be used to build up lunar energy orbs, using Wrath would generate solar energy orbs. The accumulated energy would then be used to empower special attacks, like hurricane (lunar) or mushrooms (solar) for AOE, or Starsurge for single targets. Other spells could be integrated into this system.

This way, we'd get rid of the darn eclipse bar, but we'd still play with solar and lunar energy to justify we're called balance druids.