Before I started really digging into Nim, it seemed like it was always changing the language a lot (feature churn). However, most of those changes have been compiler support for different GC's and other backend languages, which don't generally break existing code. I've tried Nim code from 4 years ago, and its almost the exact same syntax. Sometimes stdlib names changed. I think syntax change is the part that gets people a lot in terms of daily "complexity".

It actually reminds me of the feel of Python 2, before Python 3 that seems to add new syntax & language complexity every release. Well Python 2 but with a more solid language theory (e.g. everything can be a statement, etc). The trickiest part of day to day Nim are: var vs no-var, object vs ref object, and some iterator annoyances.