Quoting Righthorn at EJ's [Feral-Cat] Cataclysm Release thread
It's a tradeoff between convenience/ease and raw dps. There's three factors that make hit & expertise not required for optimum dps:
1. White hits & associated fury swipes only make up ~1/4 of our damage
2. Energy abilities that miss or are dodges do not use up their entire cost
3. We are not GCD capped; that is we have downtime between abilities while we wait for energy to build up
The third factor is what really makes hit & expertise not required. Even if you miss, because you have not expended the entire energy, and because you have free GCDs anyways, you can simply re-use the ability until you hit.
The big caveat is that, as you were made painfully aware, you really need to be able to keep on top of your buff/debuffs and be able to make quick decisions on what ability to use next. If you are able to react quickly and correctly to your misses, then you lose little dps even with 0 hit and 0 expertise, and because those stats have been converted to other dps stats (hopefully mastery) overall you gain DPS. However, if you find yourself unable to keep tabs on what's missed and what's hit and your bleed uptimes suffers, then you will find hit & exp more useful.
The most important thing to keep in mind is that your theoretical max dps will suffer if you have hit and expertise, but if you can't pull off the mechanics in reality then theory doesn't help that much.