Hi @paul l101 thank you for posting in the community and sharing that feedback! While this doesn't create a full presentation mode slide it is possible to view your document in Fullscreen mode by pressing Shift+Opt+F in Mac (or Shift+Alt+F in Windows).

This will allow you to view the canvas without the distraction of the tool bars and shape menus. Alternatively it may be helpful to create a slide of your full canvas and present that using our current presentation mode option. 

That said we're always looking for ways to improve Lucidchart and your feedback is the best way for us to do that. If you would like to see the quick presentation option become available again would you mind adding your idea to our product feedback space? Ideas discussed here are passed on to the product development team for their consideration.

Thanks for your request and I apologize for any inconvenience this causes you.