If you have a lot of sources, the current list is problematic. Trying to find a particular source is very time consuming. here is no sort order by say author, sourceID number or any other parameter nor can you search for a word in a title like TMG. TMG certainly didn't cover the need but usually could find a particular source in that same window quickly. Going out of the source list window to find a source is slow and tedious. Search everywhere is slow, moving between windows takes time and screen space. I would still need to remember if I used the exact title or modified master source title to find it in the source list window.
Several years ago I gave up on decent source management in genealogy programs. I come from an academic librarian background and instead used a separate true bibliographic/citation management system. Originally EndNote and now Zotero (free and extremely flexible). Unfortunately this requies a duplication of sources. If I'm going to go outside the source list window to try to find a source then using Zotero is easier except the duplication because the other features of Zotero are very useful (attaching links, documents, media, folder categorization, etc.)
I've found in the RM forum that people have developed source categorization techniques to try to get a handle on this issue. Rather than put that effort into RM, I'll maintain my duplicate source management in Zotero despite the duplication for now.