I'd say immature libraries, you're going to a complete ecosystem not just the language. Looking back at [https://xmonader.github.io/nim/2018/12/06/nim-good-ok-hard.html](https://xmonader.github.io/nim/2018/12/06/nim-good-ok-hard.html) I find there're lots of improvements like lots of effort on documentation and clearer error messages, but still concurrency is rough and communication and orchestration isn't nice.
lots of the available projects on nimble seem like weekend projects which is fine, but know your risks. Aside from that, nim is a great chance to reinvent the wheel for lots of things e.g wrote a redisparser, client and terminaltable! which I would never do in Python or Go world.
