the problem is not that they are completely useless, but consider that you need to stop cast for 3 globals for an 8 (10? don t remember) second slow, and you need to spread your fungus to have a decent slow zone reducing by a large amount the damage. Now think that you can easly say to an hunter to place a frost trap, with bigger radius, with more duration and 1 gcd. Or maybe have 1 of your mage go frost and blizzard em down slowing. See the problem here? 3 gcd not used are like 100k damage if you were in eclipse.
lvl 85 troll druid - Balance pvp&pve, resto pvp&pve
lvl 85 troll mage - Frost/Fire
lvl 80 troll rogue - Ass/Sub
lvl 80 troll shaman - Ele/resto
lvl 85 orc hunter - Sv/MM
Live the good side of life, think optimistic, they aren't going to nerf you <xD