Greg "Ghostcrawler" Street has stated on the official World of Warcraft forum the dev team is concerned elemental shaman DPS is "a little low," so an upcoming hotfix will improve the chance for the Lightning Overload talent to cast the half-damage Lightning Bolt or Chain Lightning.
"We think this will provide a roughly 5% dps increase for say the raid-buffed level 80 Elemental shaman, but we will closely monitor the damage being done after this change. Note that the tooltip of the talent will not change from this hotfix – the talent will proc 33% of the time with 3 ranks, even though the tooltip says 20%. We will get the tooltip updated in a future client patch."
So what do you think, ZAM shamans?