Maul spam = gone
All next-on-hit attacks are going the way of the dodo, much to the relief of everyone who wound up macroing Maul to their rotations after being diagnosed with RSI. Maul and Heroic Strike will now be instant attacks consuming a variable portion of your existing rage, with greater damage tied to more rage. Both skills were intended to be rage dumps in exactly this manner but, in the abundance of rage generation versus a raid boss, quickly made an absurdly frequent place for themselves in the warrior/bear rotations.
Bear specifics: Maul is such a huge and seemingly irreplaceable portion of a bear's threat output that we're almost certainly going to see threat modifiers adjusted on other skills in order to compensate for "losing" Maul spam. If not, expect to see something else done to make up for Maul retiring from its preeminent role in the bear rotation.
Less rage starvation (we hope)
One of the more irritating but unavoidable issues with rage is that because so much rage generation is dependent on damage taken, your ability to hold aggro in lesser content actively deteriorates as your gear improves. While this is somewhat better than it was in Burning Crusade, it's still a rare warrior or bear who hasn't found him/herself swinging fruitlessly at a pull, dependent on the pitiful rage income generated by auto-attacks. Fortunately for us, DPSers are often understanding of these difficulties. Or not.
With a set amount of rage generated by white attacks, rage generation should be significantly more reliable regardless of gear quality. And while the point concerning this was somewhat vague, rage from damage taken also seems set to scale with the health of the attacking mob. It seems sensible to assume that the greater the health of the mob (e.g., a raid boss versus your run-of-the-mill heroic enemy), the greater the rage gain from its damage done to you.
Bear specifics: Not much, really. Warriors and druids share this incredibly irritating problem, and I imagine we both share the worry that whatever the rate of rage gain, it may not be enough to compete the demands of oft-impatient DPS.
On-demand rage gain
By my count, warriors will have at least three on-demand rage generation skills in Cataclysm (Bloodrage, shouts and Charge), but there are no specifics yet on similar mechanics for bears. Furor, given that most ferals can only afford to put three points into the talent, is an irritating mechanic with a very small rage payoff, so my guess would be that on-demand rage gain gets yoked to another skill or introduced with a brand new one (given Blizzard's desire to give the bear "more buttons"). With luck, we'll get more information on this Friday, but if not, it might just be that Blizzard's still not settled on what to do.
Lower crit chance
Ghostcrawler is hinting that the amount of crit gained from agility or raw +crit rating is likely to decrease beyond the normal rate assumed by gear and level progression, and this will obviously have an impact on Savage Defense uptime. Bears are currently balanced around having that up constantly, so we may (or may not) see some tinkering with it.
I'm optimistic about how these changes will impact the problems we have with rage right now, but I will admit to a little worry over the possibility of being too easily rage-starved (hands down, one of the most irritating things about playing a rage tank). We're still competing against a tank (the paladin) that starts every fight with a full mana bar and access to everything in his arsenal, and I think it's reasonable to argue that that's been a much better fit for the direction that tanking has gone in Wrath. However, with the other changes that Blizzard's planning to make to both 5-man and raid tanking, I think it's very possible that rage could become a lot more interesting without being such a constraint in lesser content.