In this thread http://www.dual-boxing.com/showthread.php?t=24270 Ridere gave a rather wonderful macro for round robin thunderstorm with shocks added ( The man/woman's a genius).

It worked pretty good against single targets to keep them off of me, however when multiple players were attacking me and I wanted to fire off thunderstorms in quick succession it would often get held up due to shock cooldown.
(It didn't help that I didn't have talents to reduce shock cooldown).

I decided that I needed a macro that gave priority to thunderstorm and added the shocks in after .
So you target off your primary target and the thunderstorms blow away additional enemy as they run in.
(Great on the bridge at Dun Baladar in AV).

I thought I'd share it here.

shaman 1 /castsequence reset=45 Thunderstorm, Frost Shock, Earth Shock, Flame Shock,
shaman 2 /castsequence reset=45 ,Thunderstorm, Frost Shock, Earth Shock, Flame Shock
shaman 3 /castsequence reset=45 ,,Thunderstorm, Frost Shock, Earth Shock,flame shock
shaman 4 /castsequence reset=45 ,,,Thunderstorm, Frost Shock, Earth shock, flame shock

One change that might be nice (but I haven't put in yet) would be to have a modfier so this macro could
cast all 4 thunderstorms at the same time. Either just for the mana gain, or for big damage against a single target.

This works great on those pesky stealth classes that wait for a thunderstorm to go off before piling in