I think it would make more sense to have a FEATURES option to include bdeps in dep resolution, rather than having to always specify --with-bdeps=y or EMERGE_DEFAULT_OPTS="--with-bdeps=y" Some schools of thought additionally have it that that FEATURE should be the default behavior of portage. This enhancement would make bugs like bug 266861 partially moot. Reproducible: Always
I think --with-bdeps=y is probably a reasonable default for most people. However, I imagine that it might annoy some people who work with binary packages, since they might be surprised if binary packages suddenly start pulling in built-time dependencies by default.
I don't think that --with-bdeps=y should be the default. For most people it's a waste of resources. For FEATURES <-> EMERGE_DEFAULT_OPTS: It has always been an option and I don't see a good reason to change that. Especially because changing either of them requires the same work (editing make.conf). Closing as WONTFIX.