Perhaps only useful for non-coder users of Webflow, but it would be nice to see the to-be-generated HTML code while in the Designer, without having to export or publish.
No need to edit the code directly, just view only. Usage would be to see right away how editing using Webflow's GUI affects the generated code, which is a good way to learn how Webflow works and educate oneself about HTML and CSS in the process.
It would also be helpful for coders... So that you can inspect what exactly webflow does to tweak your custom code. (Which wrappers, Lightboxes etc.)
I would love this feature, currently I open preview url and then view-source/inspect element, but it would be a lot faster to see this within webflow designer without having to switch windows each time.