I tried this hybrid spec in orgrimmar dummies and in fact together with castrandom LvB LB with separate FS I get an increase in DPS of around 25% with my 4 Elemental Shaman just self buffed. I can imagine what it'll be like with raid buffs.

The most noticeable thing is, I placed 4 mana totems like I usually do and it's extremely hard to run oom... it's unbelieavable... Spammed like crazy, for about 12min (twice refreshing totems and once water shield and:

Was still at around 20% mana having done a total of 9.97k dps and 6306k total damage.

It comes basically from more shock cost reduction and not using CL I think.