What are these tools? AFAICT we are talking about cabal and stack only, and from the recent discussion it seems that stack has slightly different goals: One stack.yaml can reference vaious cabal package descriptions, something I've never use until now, because I wasn''t even aware that it is possible. :-). So apart from the different surface syntax, there seems to be more fundamental differences.

Why is this even a goal? On the contrary, I see this as an anti-goal, because it leads to useless creativity and fragmentation.

This is a worthwhile goal IMHO, but we need to be more concrete, e.g. how can repetitive stuff like the tons of almost-copy-n-paste in https://github.com/haskell-opengl/GLUT/blob/master/GLUT.cabal be avoided? This has nothing to do with syntax, more with abstraction facilities and semantics: If we just switch to JSON or YAML, GLUT.cabal would as repetitive as before, only in a different surface syntax.