> I always hope it's going to be about 'power and reliability of Bazel' but as friendly to get going with a basic make rule.

Have you seen https://please.build? It is very close to what I think the answer to "What if Blaze was made today?" is. It is conceptually much simpler and doesn't suffer from some of the things that need to happen in Google-scale projects/teams. For example, they haven't done the same gross thing with proto_library that google did. You only define one and it only builds the bindings that are actually needed by the targets you are building.