goffice versions >=0.10 has a hard dependency on libspectre, which on my system pulls in a lot of new dependencies. libspectre is only required to enable embedded EPS, in which case also ghostscript is required.
My proposal is to add an eps use flag that pulls in ghostscript and libspectre to enable eps.
I have tested this by removing the dependency on libspectre in a local ebuild. It compiles and runs fine without libspectre or ghostscript-gpl on my system.
The depend is automagic, and that needs to be fixed first: