Here's a fresh attempt to improve depend.apache.eclass; this time some of the ideas from dwfreed's patch are implemented. The initialization of two variables is shifted from global scope to pkg_setup.
We still remain with one eclass though (and what I haven't used is the new dependency/useflag code there, since it changes the interface). Impact... right now only 4 ebuilds in the tree use depend.apache.eclass with EAPI=6. Two of them use depend.apache.eclass directly, and none of the variables is present in the ebuild. Two use it via apache-module.eclass, but that eclass only uses the affected variables in phase functions.