Let me get mathematical on you for a second. In any given boss fight, we have a potential maximum DPS, based on our stats (from gear and buffs), our skill (determining the best ability priority order to follow and then following it perfectly) and luck (crits, procs, etc.) Since luck is uncontrollable, we discuss how to maximize our stats and our skill.
With that in mind, let’s look at Ferocious Bite. Using my current gear (ICC25N level) as a rough measure in Simulationcraft and my current derived optimal rotation, I can pull 11402 DPS given perfect conditions (pre-ICC buff). If I eliminate FB from the rotation, my DPS drops to 11386, a 0.15% reduction. QQ. Even for a BiS feral, who has the gear to fully maximize FB, the DPS drop goes from 14104 to 13992, or a 0.8% reduction. Meh.
Here’s my postulate: For the vast majority of players, attempting to use Ferocious Bite as part of a DPS rotation (not counting target-about-to-die situations) will complicate the rotation more, which will lead to more errors in executing that rotation. This will lead to overall lower DPS.
Feel free to discuss in the comments. :)