It would have been nice to see a comparison to nixos or guix system, which seem to be solving similar problems but without giving up toolbox-like configuration of the end state. OP seems to be heading more towards a docker-like model, where you get an image but have no idea how it was built or how to modify it.

EDIT of course this does have the advantage that you can make things appear in standard places, rather than having to modify legacy software that likes to just search around a list of directories at runtime.

EDIT published 2014 - explains the lack of comparison to existing systems.