When opening a new tab, the list of local repositories is not a hierarchical list like the old bookmarks window. When you have dozens of repos, it is painful to find the one you want (particularly if they have similar or identical names) when the hierarchical view is no longer present.
Additionally, there are gobs of useless white space between the items on the flat list that reduces the number of items visible.
The old hierarchical bookmark view was one of the main reasons I used SourceTree. I would suggest strongly that you restore this view. Otherwise the program should be renamed SourceList
I'm going to revert to 1.8.3 as this was the last version that provided a useful list of repos, and was economical with mouse movements to stage files.