I was hoping to see this fixed in 2.3. A very common editing workflow that works in ArcMap is to have many layers in a map, with most of them from AGOL/Portal/ArcGIS Server, and right click on 1 (ONE) and select "Download for offline editing". You just get that one layer. In Pro, there is no such choice, when you hit "Download Map", anything that is offline-capable in your TOC, gets downloaded. The problem is instead of waiting 10 seconds or 1 minute to get the single (1, ONE) layer you want to edit, you wait 1 or 10 minutes while all (EVERYTHING) is downloaded.
"Just have a single layer in the map" really isn't a workaround, as most editors typically reference off other layers, and firing off a separate map in the Pro project just for editing adds a lot of unnecessary extra steps and duplication where in ArcMap this operation is a simple right-click to download a single layer for offline editing.