Amd has replaced last commands starting with ati-prefix by amd-prefixed ones with release 11.8 (ati-prefixed still exist, but are just a link). So as a consequence of that, ati-drivers should be renamed to an amd-prefixed package like amd-drivers. It would be better to replace it by amd-catalyst or amd-fglrx, because it is clear that its a driver cause of its category x11-drivers and you won't think you need it as a "cpu driver" or sth like that. I prefer amd-fglrx, because it's shorter than amd-catalyst and you won't mix up with dev-util/catalyst.
The filename is already unrelated and I see little point in changing it now since it doesn't provide any advantage. Thank you for the notice regarding the namechange upstream, though
Everyone knows the driver as 'fglrx', and emerge --search fglrx and eix fglrx currently show nothing.
The main reason is, that it is much easier to find for new Linux users or users switching from other distributions to Gentoo. Debian: fglrx-driver Fedora: xorg-x11-drv-fglrx Slackware: fglrx-driver Plus: All supported cards were released after AMD purchased ATi.
How other distro name the driver is fairly pointless. We might add and fglrx reference in the package description.