LangChain co-founder here. There's lots of good feedback here (that also resonates with previous feedback) that we're working hard to address. On some key points:

- We genuinely appreciate all the thoughtful criticism and feedback. Our goal is to make it as easy as possible to build LLM applications (both prototypes and production-ready applications), and if we're falling short in an area we'd much prefer to hear it rather than not. We don't have the bandwidth to respond to all feedback directly, but we do (1) appreciate it, and (2) try to address it as quickly as possible.

- Documentation: we've heard this for a while now, and have been working to improve it. In the past ~3 weeks we've revamped our doc structure, changed the reference guide style, and worked on improving docstrings to some our more popular chains. However, there is a still a lot of ground to cover, and we'll keep on pushing. Feedback on which specific chains/components need better documentation is particularly helpful

- Customizability: we need to make it easy to customize prompts, chains, and agents. We're thinking of changes to more easily enable this - better documentation, more modular components. We'll up the priority of this.

- Other tooling: there are general difficulties in building LLM applications that aren't strictly related to langchain, such as debugging and testing. We're working on building separate tooling to assist with this that we hope to launch soon.