The two forks of NI are:
- Agility becomes +healing
- Cat form gains 20% extra incoming heals
Now, if one considers that even a feral druid might be called on to heal, then the agility to healing looks very tempting. However, you shouldn't be called on to heal in your agility gear. And if you are then all the +healing in the world is unlikely to help you, since you're mp5 and mana pool are going to be totally gimped. You might get +500 healing from your agility, but if you're only able to put out 30 seconds worth of healing (for the rest of time, since you have no spirit either), what will it matter? It could be argued, I'll admit, that since your base agility is 66 then this will always yield at least +66 healing. It's a nice amount just from a talent, and if you were a healer and it was in the restoration tree then it would be a very nice talent. However, I personally don't have two points to spare, especially on making myself better at a role I've no desire to fill. At the moment I am trying to free up two points for Shredding Attacks which I should really have since the natural position for druid tanks is off-tank, which means we spend a lot of time filling a DPS role as well. Trying to then find another two points for NI would be even harder.
The other fork of this talent, +20% healing recieved in cat form, might be quite nice. I have healed as a holy priest, and I know that it's nice to heal a warlock because they take extra healing. However, I don't factor in the fact that a lock takes extra healing when I hit my button, so I end up over healing them a lot. I imagine the same taking place in this case. The healer wont be paying a lot of attention to the druid's form when they throw out their heal so there will be no increased efficiency.
I firmly believe that NI is a PvP talent. Where it will shine is when the druid shifts, spams a few heals on themselves and then shifts back to cat, meaning that heach heal has their +agi-as-heal on it and each heal over time has their 20% healing on it. Which would be very nice indeed and might mean the difference between life and death against a player. A raid boss isn't so easily impressed, though.