I object to making the packaging system more complex without a real gain. We should better document what "Build-Depends-Indep:" really mean: That which autobuilders do not need to install to produce Architecture: any packages via the clean, build and binary-arch targets only.
We could well keep Build-Depends-Indep: for things which are only used by the binary-indep target (which is how things really work today), and deprecate the build-arch and build-indep targets, since they have never been really useful.
