- its module system, especially not being able to have mutually recursive imports (there has been a 7 year old proposal[1])
- order-sensitive declarations of procs (i.e. can't use a proc defined further down in the file unless you add a forward reference to it). For the latter there's an experimental pragma[2], but it doesn't work a lot of times once you introduce mutually recursive calls
- object variants requiring declaration of a separate enum instead of allowing inline declaration of the variant cases, and a close issue[3] with not being able to define the same field names under different variant cases.
[1] https://github.com/nim-lang/rfcs/issues/6
[2] https://nim-lang.org/docs/manual_experimental.html#code-reor...
