Granularity is an important point, yes, but even for the right "granularity" the basic math is completely against you: If you have N dependencies in total and every dep only has different 2 versions (say 1.0 and 1.1) and every dep claims to work with 1.0 ..< 2.0 that's 2^N combinations which in practice effectively nobody tested. And in reality it's 2^N * 8, 8 standing for the 4 common OSes and CPUs (let's say Win, Linux, BSD, OSX and x86_64 and ARM). And that ignores the different underlying C compilers that Nim uses, its "C vs C++" code generation modes and different Linux distributions.
IMHO we need to guide our community more how to write software that can be trusted, encourage people to submit their quality code to a **common** github repository to avoid the problem of combinatorial explosive test matrixes. We need to work together, not on isolated github projects.