Details are coming out about the new cards.
It does seem like more of a refinement and rebalancing of the cards they offer, rather than pushing forwards for higher and higher performance levels, at least with the initial new cards. The current 5770 is being rebranded to 6770, and the 5850/5870 are end-of-line to be replaced by the 6850/6870.
One interesting thing I picked up on at SemiAccurate:
On a more positive note, there is a new anti-aliasing (AA) mode in the 6000 series cards called Morphological Anti-Aliasing (MOO). Instead of the traditional AA modes, MOO is more of a post-processing step. After a scene is rendered, MOO goes over it and looks for edges, and takes out jaggies.
Because of this, it should work everywhere, on any game, or even with non-game software. Even if a competitor decides to lock ATI out of AA modes and put contractual wording in their brib^h^h^h^h paperwork to prevent a company from doing the right thing, MOO should work.
It seems a nice way to short-circuit any silly dealings like was (allegedly) seen with Nvidia exclusive anti-aliasing on Batman:AA. There seems to be a emphasis on better image quality with these cards too, I'm not sure if that's rectifying shortcomings in previous cards though.