The package does depend on dev-python/pysqlite:2 but not on Python implementation USE=sqlite. The pysqlite package is no longer maintained and compatible with Python 2 only; while the builtin 'sqlite3' module is basically a maintained clone/fork of pysqlite. If the package actually imports pysqlite2 unconditionally, please check whether it wouldn't work with the builtin 'sqlite3' module as well. If it does, upstream should probably fix the package to import 'sqlite3' *at least* when 'pysqlite2' is not available. If it doesn't, please let us know and we will know that pysqlite needs to be kept in the tree. If the package simply supports 'sqlite3', please let us know or update the deps. However, the latter is unnecessary since the 'old' Python eclass doesn't provide a proper way to do this, and we may decide to drop pysqlite entirely after getting feedback for the packages depending on it.
afais the dev-python/pysqlite:2 dep is actually wrong, it does not import it anywhere, it actually imports 'sqlite3' already...
+ 16 Jan 2013; Julian Ospald <hasufell@gentoo.org> pychess-0.10.1-r1.ebuild: + fix deps wrt #452142 make a stablereq for that version if you need to resolve the blocker