Frost, ice lance, ice lance, frost… Rinse and repeat. This is the most common attack combo from virtually all mages in the game currently, simply because it is the only active combo in the game. There are certain things that I feel the runemage is lacking, two of which are a use for their left hand, and being able to cast/attack while moving.
I propose that there should be a way to enhance the effects of certain spells, with a cost of time.
Say, for example, you cast frost 1. Taking a spell’s tier number (1, 2, 3), with this case being tier one, and multiply that by a certain number gives you the amount of time it requires to “charge” the casted spell. Charging simply consists of pulling the trigger on your wand hand. This could be done while moving.
Once charged, any charged spell gets transferred to your left hand, and becomes a close range attack that does an enhanced effect. Enhanced frost would freeze a target for the tier number in seconds (tier 1=1 second, tier 2=2 seconds, tier 3=3 seconds), enhanced fire would do fire damage over time like the dragons in the burning forest for 2*tier number (tier 1=2 seconds, tier 2=4 seconds, etc.), dealing damage over time for 3 seconds.
All enhanced spells would be a close range (1-2 meters?) and would come from your left hand simply to make it feel useful.
Here’s a list of each spell using a charge/enhanced effect, along with charge/dot duration.
Spell / Charge time / Effect duration / Effect type
Fireball one/2 seconds/3 seconds/DoT
Fireball two/4 seconds/6 seconds/DoT
Fireball three/6 seconds/9 seconds/DoT
Frost one/2 seconds/1 seconds/Stun: Frozen
Frost two/4 seconds/2 seconds/Stun: Frozen
Frost three/6 seconds/3 seconds/Stun: Frozen
Ice Lance/3 seconds/Instant/Damage: 10% bonus, single target
Affliction one/2-3 seconds/Instant/Damage: 90% of normal DoT damage all at once
Affliction two/4-6 seconds/Instant/Damage: 85% of normal DoT damage all at once
Arcane ray/ 2 seconds/4 seconds/Weakness
Arcane explosion/3 seconds/1.5 seconds/Stun: Confusion, Weakness (Single target: nearest mob, 3 seconds)
Arcane Missle/2 seconds/4 seconds/Weakness of nearest enemy
Decurse/2 seconds/4 seconds/Resistance to first status effect such as poison within duration.
Mana shield/2 seconds/3 seconds/Returns 80% of damage taken to enemy when damaged by a melee attack.
Light/5 seconds/15 seconds/Adds slight health regeneration when allies are within 3 meters.
Polymorph/2 seconds/Instant/Changes the animal polymorph changes enemies into (for fun) 
If I missed any spells, let me know!
EDIT: Any enhanced spells would cancel out previous spell effects. For example, enhanced frost doesn’t do slowness, only freezing. Enhanced fire doesn’t do lots of initial damage, only damage over time, etc.
