Blizzard made a few attempts to fix Force of Nature — the problem was that they would start to walk around and act crazy if their Wrath cast time was less then that of the global cooldown.
First, Blizzard increased the cast duration from 2.0 seconds to 2.5 seconds (while increasing the damage by 25%). This helped, but with the meta gem proc and Nature’s Grace, it was still very easy to hit the global cooldown.
Next, they reduced the global cooldown to .5 seconds. This has solved the problem. Force of Nature seems to be very viable on most of the fights in ToT. Enjoy treants that for the first time in WoW history … don’t suck!
Also, a small hotfix was made to Solar Beam. It seems you could spell reflect the silence back onto yourself: