I fully agree. I always found/find Helm underwhelming. Maybe I'm just using it wrong.

What I want is a Maven for Kubernetes. With transitive dependencies, strong conventions, injection of parameters etc.

The templating stuff feels very...unstructured to me. Every Chart is slightly different.

I share the same sentiment. Still looking for the holy grail but the best lead so far is using the combination of Bazel (excellent dependencies support), its rule for wrapping around good templating solutions (jsonnet, ksonnet, etc.) ; and some backend that integrates with infrastructure tooling to generate configurations to fetch into bazel.

Helm + Kustomize [0] to add in whatever wasn't in the helm template works pretty well IMO. Kustomize is pretty new and not the most user friendly though.

0: https://github.com/kubernetes-sigs/kustomize