<=net-print/cups-1.3.11 had a 'ppds' useflag which installed the foomatic-filters. I suggest adding it to cups-1.4 as well, as the filter files are still needed. The necessary changes can pobrably be copied from the 1.3.11 ebuild. Reproducible: Always Steps to Reproduce:
ping? :)
foomatic-filters are only needed for a special set of printer drivers, thus should be depended upon in the individual printer driver ebuilds. Furthermore CUPS can generate ppd files on the fly now utilizing the included cupsddk and the whole foomatic stuff needs some changes, cleanups and a bump. I'm working on it, but my time and hardware testing capabilities (except HP) are limited.
@Timo: What would you suggest as a short-term solution?
I'd help if the reporter would have stated which printer driver he actually uses so we could fix that instead of polluting CUPS with false dependencies. As for CUPS, resolving as WONTFIX. Please open a new bug for the printer driver which is missing the foomatic-filters dependency so we can fix this bug properly.