It seems to me that there are 2 competing ideas, or perhaps requirements there:
- the need for a well rounded set of libraries working seamlessly together
- the need for being able to install libraries with as little pain as possible
My understanding is that OPAM so far tries to address the second point, not the first (maybe I’m wrong?). Apparently it’s not doing enough yet according to your friend, but my impression is that it would be worse without it - or rather, that the situation is much better with OPAM than without.
Also, the first problem is really a distribution goal, rather than a package management goal. Many Linux or BSD distros have been working on that second point for a long time, and often do provide a consistent set of libraries for people to install and use easily. So unless you’re looking for very exotic libraries, perhaps your friend should consider using a distribution/his distribution packages, and fall back to OPAM when the package he need isn’t supported there? Besides, OPAM accomodates very well with that setup.