I'm not sure what you mean by that, surely word processing is exactly what Quill is meant to be used for? Table use outside of word processing could just be achieved by something other than Quill entirely.
> tables are just not used very much. ... None of the big sites using Quill are clamoring for tables.
That's fair enough, I doubt they would be used in the context of writing an email, blog post (but that is debatable, I often include tables of figures/results) or a task manager description. But there are many, many back office applications that take user input through a WYSIWYG editor and put it into some kind of report. I think tables are critical here (I was also surprised to see nested lists[2] are not supported in Quill, that's also pretty important). Maybe Quill isn't aiming for those kind of use cases though, but it's just such a shame that TinyMCE is the best solution.
It's possible to do right, we used to use Redactor[1] and that handles the basic use cases extremely well while producing super clean output.