Bare in mind the buffs required to actually have 2005 be your breakpoint, it's also possible you are hitting that number without realizing you require additional haste buffs provided your raid composition which may not be present in a ten man. Provided you have the necessary buffs, that breaking point is for an additional tick on Wild Growth. Wild Growth is not a tank healing spell so naturally this won't help as much in this particular context, though overall you would want to keep it.
I'd personally recommend ditching Nature's Bounty talent. That talent is still quite lack luster overall. If you are doing considerable tank healing you will likely prefer to swap to Living Seed, both are weak talents but Nature's Bounty is generally considered the weaker option. Extra point in either Furor or Genesis.
I'd also recommend ditching Glyph of Innervate in favor of Glyph of Healing Touch. Nature's Swiftness was buffed and is quite useful now and since you will be tank healing you can expect to shorten the cooldown to almost half because you will be casting a fair amount of Healing Touch. You should also be getting in the practice of using Innervate on yourself instead of other healers because 4.2 will change it such that the value is severely deminished on anyone else.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.