First scrap Rage I mean Maelstrom as a mechanic.
New resource mechanic: elemental motes - builders generate motes for storm, fire, and earth. Spenders cost 1-3 motes depending on the spell, and have various length cooldowns.
Example skillbar:
1 - Elemental Bolt: Rotates between Lightning, Flame, and Earth spike. Same base cast and range as Lightning bolt. Generates 1-2 elemental mote per spell.
2 - Lava Burst: Medium Damage, costs 2 fire motes. 10 second cd.
3 - Earth Shock: Medium damage, costs two storm motes. Instant. 10 second cd.
4 - Earthquake: Medium damage AoE, costs 2 earth motes, instant.
5 - Chain Lightning: AoE damage costs 1 storm mote
6 - Elemental Blast: High damage, Costs 1 of each elemental motes, 12 second cooldown.
Plenty of new spells could be added. Talents could change all sorts of parts of a system like this. Add mote costs for additional effects, add optional spells to generate more motes, cooldown resets for various spells etc.