The GCD floor is 1 second, correct? Most shamans at decent 80 gear probably are sitting at 300 haste, which is reduction of nearly 10% to 1.35? So you would be saving 0.35 seconds. In 60 seconds on PVE boss fights you would cast at most 4 flame shocks (every 18 secs) so you are saving 1.4 seconds to cast DPS spells, doesn't seem very effective.

For PVP of course you may cast a lot more FS's and saving 0.35 seconds on opening burst is huge, especially with 4 shamans. But for PVE its never been a big deal, in fact many times I have to wait around for the tank to build up enough threat.

Niley - in recount how much of your damage is lava burst vs lightning bolt on boss fights? I haven't run naxx on a shaman this week but in heroics lightning bolt is > 50% of my dmg still on boss fights, so I prefer the crit glyph (to keep aura always procing and to help LB) to LvB glyph.