I feel like “bad design” is too reductive. The article is an attempt to explain why it’s bad. What are the practical problems it introduces?

I think it could go a little further in explaining what I think the root cause of the issue is: the people developing this mini framework do not have the time or focus to turn it into a full framework. Compare to Django, Rails, React who, whatever your opinion, clearly have time and mission to build, test and document a framework for others to use.

The very nature of working for a SaaS company means your true goal is to build shit for your customers. Any internal tooling has to overcome this large hurdle to get the attention it needs to be able to truly thrive. And rightly so.