How often does that really happen though, in terms of needing it for general system usage? I have worked in Windows all day for my entire career and it hasn't come up much. When it has, notepad is almost always sufficient to deal with the edge case.

For other kinds of text editing, just download and use whatever text editor has the features you want for the task at hand. If notepad had to be all things to all people it would be bloated and not particularly good at anything anyway, so it's better that it remain a lightweight simple text editor in my opinion.