Hello. It would be a nifty feature for the OmniGraffle to have a "dashed underline" style for the text, since it's used on the most modern sites, so it would be good to have it for the site projects right in the application. And, I am quite sure that it's easy to add.

Also, OmniGraffle has variables for different canvases, and it would be good to make this variables accessible as the variables in text boxes and such.

And the last option is to add a checkbox "export canvas names" in pdf export. Most people make meaningful naming for the different canvases across the document, and when you send the results of your work to someone, it's just necessary in most occasions to specify page names somehow.