You can pretty much catweave every boss, just the amount of catweaving you can do depends on the mechanics. Even on fights without real swaps, most bosses have some big telegraphed attack with a long cast bar, and that is where you can squeeze in some cat time. With the new changes, it's more efficient, as Rake > Shred > Shred > Rip will get you a rake with a 16 second full damage rip off of a full energy bar.Raid tanking might be nice on bosses we can catweave though, for the people that care about doing optimal DPS. Maybe we won't be top for that even still, though.
As far as what we can expect, it is quite possible for Bear dps to be #1 on single target. For AoE we should be definitely better than we were, but still not as good as most of the others. They should think of a way to fix this too, and it seems obvious to me the key to that would be something tied to Thrash.