I am not sure if this has been addressed before but I figured I would ask since no one on my server has answered it for me yet. On WoW's bug page under the "issues that are not bugs" section, it states this...
5. Buff/debuff tooltips do not show the bonuses from talents.
Example: Improved Thunder Clap tooltip says it slows by 10% instead of 20%.
The tooltips for buffs and debuffs do not update to reflect talented versions of abilities. Although technically this is a bug it is caused by a limitation in the buffing system and cannot be changed at this time.
Does this mean that with 3/3 Imp TC it actually slows by 20%, but only shows 10%? Or does this mean that Imp TC only helps damage and does nothing in regards to adding 10% extra slow? I hate to use 3 whole points if it is only adding a relatively small amount of damage for those points. Thanks guys.