I could not find any rationale either, aside from "this list came from Marcin's head".

> Maybe there should be a starter subset like GVCS5 or -10.

I have taken the Systems Engineering approach to the problem (which is what I did professionally before retiring).  The results so far are embodied in a wikibook:  http://en.wikibooks.org/wiki/Seed_Factories  I cannot say for sure what the starter set will have in it, but I have an example of what it *might* contain in section 5.2.  The analysis process I am following is in the notes (section 9), especially page 8.  It starts with defining what outputs I want from the system, primarily food, shelter, and energy.  Then you work backwards to identify what equipment is needed to provide those outputs, and in turn what starter set is needed to build that equipment.  I am trying to develop a general design process, so that if you have a different environment in a different location, you can follow the process and come up with an appropriate design.

The work is far from finished, but you can see what is there, and it's open source like OSE is.  I participated here in OSE for a while, until if found things were too disorganized and undocumented.  So I have chosen to try and put the concepts on a sound engineering footing.