So with all the juicy AP and agi, how awesome are most feral staves going to be for Hunters? Very, very, very. Does this mean that ferals are going to have to roll against Hunters for their weapon now? Yup, totally. Is this catastrophic (pun semi intended)? I don't think so.
For those that raided SSC, how many feral staves got sharded? In most guilds, a ton of them. Then again in Hyjal, same thing. And, consider that weapons other than feral staves will be good for ferals now, like the ones that, you guessed it, Hunters would have been drooling over. In the end, this is probably going to mean a bit less sharded gear, and a more well geared raid. If it pans out like that, this weapon change will be a really good thing.
I guess the big question is this: Will this hurt cat DPS and/or Bear tanking? Blizzard of course says no. I have seen these kind of changes not work as intended too many times to beleive it until I see it. It's probably not going to be that big a deal, but you never know.