I haven't used LangChain, but my sense is that much of what it's really helping people with is stream handling and async control flow. While there are libraries that make it easier, I think doing this stuff right in Python can feel like swimming against the current given its history as a primarily synchronous, single-threaded runtime.

I built an agent-based AI coding tool in Go (https://github.com/plandex-ai/plandex) and I've been very happy with that choice. While there's much less of an ecosystem of LLM-related libraries and frameworks, Go's concurrency primitives make it straightforward to implement whatever I need, and I never have to worry about leaky or awkward abstractions.