It might be worth mentioning that if your raid typically has either another boomkin who always casts FF (and is specced with 3/3 improved FF) and/or a shadow priest you can completely ignore FF in your speccing. Personally, I typically raid with a SP as well as another boomkin who has improved FF, so I have been able to ditch the improved faerie fire and just focus more on DPS increase talents (Imp IS or Brambles).
My off spec is actually the same thing as my main with improved FF in case of emergency.
No. Brain before posting, even just a little. iFF is 3% crit to all of your spells any time an FF is up. If you have a feral tank, they'll put it up. If you have a feral DPS, they'll put it up. If you have another moonkin and no Spriest, one of you will put it up. In fact the only reason that FF wouldn't be up is if your only other Druids in the raid are Trees, and you have a different class putting up the 5% armor debuff (CoW or Sting from a Wasp). Otherwise, you should be putting it up anyway, because that 5% armor is a great raid debuff. And even then, if all the raid debuff slots are covered, you should STILL put it up because 3% crit personally is worth spending a GCD every 5 minutes.
And 3% crit to all spells is just plain better than iIS, or Brambles, or any of the other "filler" talents after you've gotten all the necessary ones.