Feature request: replace document styles with library styles
Now that Sketch supports layer and text styles in libraries, it would be awesome to take full advantage of library styles for existing files, too. What we need is a feature working a bit like Symbol Swapper which allows changing some/all text and/or layer styles in the document to use the styles with the same name from the selected linked library. 
My preference would that this would also support shared libraries in Abstract so that team can benefit, too.
Personally, I find the missing feature to be more urgent for text styles as there tend to be hundreds of text elements in each project and changing them manually takes hours per project.