A fair warning, if you do not like reading math or wild speculation, then this post is not for you. I will do my best to keep everything as simple and easy to read as possible, but no real promises.
With that out of the way, it's time to get into the core of the matter. Right now, balance druids have a serious problem when it comes to Wrath and the GCD. Although the main culprit of the issue is Nature's Grace, which causes us to cap the one-second GCD at 400 haste, that isn't our only real issue. Haste effects have scaled a bit out of control in this expansion as a whole, and it seems that in Blizzard's attempts to make us utilize both of our main nukes, they have forgotten to take that into account. Just as an example, even without Nature's Grace, Heroism makes Wrath practically unusable by blasting through the GCD without a worry. Even back in Trial of the Crusader, when we were still trying to cap our haste as close to 400 as possible, it was an issue, so it isn't a wonder that Icecrown Citadel has been much worse.
The gear scaling issue is one that Blizzard has said they are going to address in the coming expansion; however, will that really be enough for us? Even back in Naxxaramas it was more than possible to get well over 400 haste, which was before the gear scaling issue even took effect. I've already talked about how Blizzard has stated that Nature's Grace is going to have to be changed come Cataclysm, but is Nature's Grace really the core issue here, or it is Wrath's cast time itself? Ask any shadow priest and they'll tell you how troublesome it can be to work with a 1.5-second spell even without all of the complications that balance druids have. For a cooldown-based spell, it might be more acceptable; when dealing with a main nuke that's constantly being chain cast, it becomes a more complicated issue.