A similar idea is suggested here by @ChadKopplin, but it seems to have been closed as the user's use case was mostly satisfied by Pro's catalog view. However, it got a significant number of upvotes, and I also find catalog view frustrating for reasons detailed here. If there's not going to be a standalone ArcCatalog replacement that supports this, Pro should support dragging and dropping from any origin - especially origins made by Esri. Who does it make sense to to restrict that? Even Windows Explorer - which is a horrendous way to view GIS data, but here I am doing so - supports drag and drop.
In the early 2010s, websites started to widely support drag and drop for file uploads and the like. In fact, some websites began to convert their whole page into a drop zone - much like an open map in ArcGIS. I seem to recall parts of Google actually upping the heat and adding the text "Or...if you prefer..." as a taunting prelude to their newly-demoted grayed-out microscopic "Browse" button. They wanted you to drag-and-drop, and we caught on. We've gotten really used to dragging and dropping whatever from wherever to wherever because it is intuitive and functional. macOS has revolved around drag and drop for decades. To me, it's an equivalency issue. Not supporting such a functionality is a confusing step backwards for end users - especially when it was possible in the past with prior Esri products and some file types (such as .txt) are drag-and-droppable.
