Call me crazy, tell me I'm experiencing the Mandela Effect, but I could SWEAR before you went and implemented the Report Suites at the PANEL level that I could copy a Visualization on a project, go to an open project in the same suite on another tab of my open browser, right-click a visualization and then select Insert Copied Visualization.
In fact, I have to have done this enough times that this can't be a false memory. Otherwise, WHY WOULD I TRY IT??
This is really frustrating, and it's creating so much more work. You need to turn this back on, because it is a real productivity killer!