The problem is: the talent is much deeper in the balance tree than most restos ever go, and to reach it would require giving up deep-tier resto talents. At full 3/3 CF, a druid would have a 18/0/53 spec, which is a far cry heavier balance than healing trees have seen in a long while (being that most have been at most 14/0/57 or 11/0/60 in WotLK, depending on their usage of Nature's Grace).
Four key talents will probably see the most debate on which to drop or keep, and which one(s) each druid chooses should depend on how useful you find them in your situation as a healer in comparison to the 3% haste. As far as I can see it, if you take 3/3 CF by spending 4 talent points to get past the previous 14 spent by restos in the balance tree, you will only have 3 talent points left over to split among these 4 different talents (the link put one point in revitalize just to open the end talents):
- Empowered Touch: not taking this is a nerf to your NS+HT emergency heal and your nourish. If you don't use either of them very often (read: never), then this may easily be passed by you; if you have to tank heal at all or heal in hardmodes on cutting edge progression, you may not have the luxury of skipping this talent.
- Living Seed: again, more of a tank-healing talent, as it is a reactive spell that will proc off of crits and heal in reaction to a hit. If you just sit in a big raid casting not but WG and rejuv, then that's not a problem. If you do more than that... perhaps it will be harder to give up this talent.
- Revitalize: a talent more for the raid-healers than the previous two, as it procs energy to your buddies off of your rejuvs and WG. If you make heavy use of either spell (which is the vast majority of druid healers, even those that do tank heals), it is well worth the investment of talent points, particularly for your energy/rage/runic-power-using comrades. While it does not help the druid as much directly as other mana-giving buffs, it boosts others' dps and threat.
- Imp Barkskin: if it was taken before, it will probably be the first to go if the druid doesn't pvp heavily. The talent does not impact actual healing, only damage reduction, which is mostly useful in solo, pvp, and cutting-edge hardmode content where the druid needs to use barkskin to absorb damage (examples include XT-002 and Anubarak).
Alternatively, you could loose two points out of Nature's Bounty in favor of keeping Empowered Touch (as with this spec); you will loose 10% crit from nourish and regrowth, but you'll keep your boost to HT and all of your nourishes. Crit rate on Regrowth is far less of a concern now, though you'll want to consider whether or not the crit on nourish is as useful for your healing as other options.
Personally, I doubt I will take CF, as spending 4 talent points on 3% haste seems very unbalanced to me in comparison to spending those points in (as I have now) emp touch, living seed, and revitalize. I am in a 10-man progressive-raiding healing situation that requires more than just "raid healing" from me, so spending 4 talent points to get 3% haste (when GotEM is 4 points for 8% haste plus an additional gcd reduction on LB) just doesn't seem worth it when I compare what else I could spend those points on. I need more versatility. This will probably be my spec (which isn't much different from my current). I'm considering maxxing living seed in trade for 2/3 Nature's Grace, but their relative bonuses and NG's semi-disruptive impact on my healing "rotation" of GCDs are hard to compare against the times I need NG for MT healing. I'm still pondering that :)
I imagine those that will find the most use of taking 3/3 CF are those druids who spend the vast majority of their time raid-healing, at which point I would suggest spending your last 3 points in 3/3 revitalize, out of the above listed talent options.
What are your thoughts?