Basically on their builds in beta, Elemental has comparable single-target dps to other casters.
But on trash they're lacking the AoE power of most other casters.
Which causes Elemental to fall a bit back on the meters.
Sure trash dps is much less important then boss dps, but people look at the meters and say...
Why did <insert class> do 900 DPS more then my Shaman.
If you were to do 400,000 damage on the trash AoE pulls, instead of 35,000 that issue wouldn't be there, or maybe not as pronounced.

Scaling is the main issue they need to look at. I could care less if I'm top or bottom dps for trash.
Having the same relative dps to other casters in both Tier 7 and Tier 9, rather then static non-scaling boosts to bring us to parity is T7... and fall behind as gear improves, just like we did in tBC in T5/T6 content.

Then again, if they want to give me a strong AoE, I don't mind if my numbers are better for a run.
I'm just hoping its something more like Arcane Explosion (macro-able) rather then Blizzard (click the ground).