I agree with you that Keyczar is good to use for certain use cases, but that isn't always the case. Instead of always telling us to use Keyzcar how about showing us how to use the primitive libraries more correctly to have secure applications YET at the same time allow us developers to have the flexibility to use them as we need to use them for compatibility with other implementations or with government requirements (for those of us in the gov't contracting world).
You are in the unique position that you have seen all of the mistakes and know how to avoid them and thus could help developers avoid those mistakes as well.