I have been a shaman since Molten Core days and I was lucky enough to witness the class evolve every expansion. I observed that Blizzard seem to be consistent with keeping the class and enhancement specially feel "primal" and "wild" and slightly more simple than the other classes which is evident from their reluctance to implement a resource mechanic.
I would like to make a few suggestions that are in line with or close to Blizzard's consistent idea of the spec.
Also has a chance to trigger when Lightning Shield deals damage.
It doesn't seem we are getting one to keep the spec unique to other melees in game. One should expect though much better range capabilities (outside of ascendance) from an elemental warrior themed spec.
To become ranged. I think 20 yards should be enough.
Fire Nova 10 sec cd (Shared with Lava Lash)
Radiates outwards from the shaman now with increased radius and damage. It has a 30% chance to afflict targets with Flame Shock. If three targets or more are hit by Fire Nova, then Lava Lash cooldown is not triggered.
Now also increases the damage of Fire Nova.
Now an elemental-only imbue which makes Unleashed Fury easier to balance. Off-hand imbues are for utility only which are Rockbiter and Frostbrand. Rockbiter only taunts targets off non tank players. Also, shields can now be imbued.
Now this may not be relevant to enhancement but I thought it might be interesting enough to include here. Now that Flametongue is elemental only, it can be made more interesting for the spec. For example, it could transform our auto attack to pure fire damage that is increased by spell power. It can be our filler when target is in melee range or when silenced. Earthliving could in the same fashion make the shaman's auto attack deal pure nature damage and heal nearby allies. Our own atonement!
This can make staves and interesting alternative to shields too.
• Shocks no longer share a cooldown.
• Rockbiter Weapon removed.
• Flametongue and Frostbrand weapon combined to become Frostfire weapon for Enhancement.
• Windfury MH/Frostfire OH
Stormstrike - Instantly strike an enemy with both weapons, dealing 380% weapon damage and granting you an additional 25% chance to critically strike that enemy with your Lightning Bolt, Chain Lightning, Lightning Shield, and Earth Shock for 15 sec. 10 sec cooldown.
Primal Strike - You charge your off-hand weapon with lightning, instantly dealing 300% of that weapon's damage to an enemy target. 2 charges. 8 sec cooldown.
Storm Surge - Your Earth Shock ability makes your next Primal Strike deal 50% more damage. Lasts 8 sec.
Lava Lash - An area attack that causes 100% weapon damage as Fire damage and ignites enemies with your Flame Shock ability. 10 sec cooldown.
Fire Nova - Create a circle of flame that radiates outwards dealing 1481 to 1720 (+ 30% of Spell power) Fire damage to enemies within' 10 yards. Targets affected by Flame Shock will ignite and be dealt 291 (+ 21% of Spell power) Fire damage. 4 sec cooldown.
Maelstrom Weapon - When you deal damage with a melee weapon, you have a chance to reduce the cast time and mana cost of your next Nature spell with a base cast time shorter than 10 seconds by 20% and to increase its damage and healing by 5%. Stacks up to 10 times but only 5 charges can be consumed at any one time. Lasts 30 sec.
Static Shock - Your auto-attacks have a 25% chance to deal damage equal to a Lightning Shield orb while Lightning Shield is active.
Obviously there's room for improvement, but I'm mainly focusing on what the new Lava Lash/Fire Nova would have to offer.