Word, PowerPoint, Excel and several third party applications support MIP labels to flag the sensitivity and confidentiality of a document, apply protection and enforce display of content markings.
Visio diagrams include just as much sensitive information as these other document formats, and users should be able to label them in the same way with a consistent user experience. Visio already supports the older RMS protection capabilities, but labels would offer a much better and more complete user experience.

I would like to see a feature where when you are co-authoring documents that have an excel data source, anyone can refresh the data. At the moment, this is not possible.

Be able to provide HEADING and TITLE variable in data visualizer wizard.

I create a lot of process/business workflows with butcher paper & sticky notes. It would be great if I could take a picture of what I was working on & upload it into Visio. Then, all I would have to do is check to make sure everything was correct (and edit, if needed).

It is very useful that Visio can create 2D floor plans, import CAD drawings, and link Excel data to shapes.

However, a greater functionality would be including a view window (or separate windows with URL for posting in SharePoint site) showing the 3D rendered model of the 2D floor plan.

Here is an example from another software company.
https://samposoftware.com/wp-content/uploads/2014/11/image008.png

Allow a user to set more default options such as connector thickness, color, and fonts. Plus the ability to select all "like" objects for formatting purposes. Formatting seems to be one of the biggest bottlenecks and time wasters.

can you copy a layer from an existing one? selecting multiple items with different layers to then apply an additional layer ends up pushing all of those objects to the common layerset = pain. If you could copy an existing layer objectset then the number of subsequent edits are drastically reduced.

It would be really good if the Layers dialogue box was independent from the drawing i.e. you can flip through layers AND THEN EDIT THE DRAWING with the layers box still open. Locking the diagram whilst the layers box is open is a pain!

VISIO + SHP: Would be great if the Export to PDF function would be available without checkout, as it is in all other Office applications.

PowerPoint & Visio folks, Could you work together to unify the key presses for precision movements for shapes? In PowerPoint it is Ctrl+right/left arrows whereas in Visio it is Shift+right/left arrows.

My preference would be for Visio to update with Ctrl+...

On high res monitors the shapes are very small. Either use DPI settings or let users zoom the shapes pane.

It will be very helpful for us if we have an option to convert PDF format to visio format.

Users are frequently torn between making diagrams in PowerPoint vs. Visio, because Visio is much more powerful, but end users can't edit them once the image is transferred to PPT. It would be extremely useful to be able to make a diagram in Visio and export it as an editable PPT/PPTX file.

Add C4 support. In our architecture diagrams we want to be able to navigate by zoom in, zoom out like in BingMaps!

It would be more attractive in the software to update the photorealistic icon shapes, so the diagrams have a relevant and professional visual impact, similar to how it does ConceptDraw DIAGRAM.

It would be great to generate flowcharts automatically from Access database like it is done with Excel.

allow color by data to color a shape based on the value of a linked cell rather than a row

If you have more then 1 time-line in a drawing have an option to automatically align the time line i.e. if 1jan2020 is in one time line and as well in the other those dates align Horizontally (or ask via pop up at what date they should align). That brings me to my second point scaling, if you have more than 1 time line where size it that a year is (e.g.) 1inch long, there should be apply to other time line option so that the other selected time-line years are also 1 inch long