The Overall User Experince
While I love the "Swiss Army Knife" approach to Adobe Premiere Pro, I think that this is part of the reason for all of the issues. Here are just some of my thoughts for the 2019 CC release. I think there are several areas that Editors would really appreciate improvements, or more completely new features for the platform.
The first is improved Metadata, tagging, and Keyword support. FCPX does this best. It is very easy to organize and sort footage based on Keywords and then search for them later on. Premiere's search box has never really worked.
Another big improvement that would a welcomed addition, is an Active Index list. Both Blackmagic's DaVinci Resolve and FCPX have this feature. To make this effective, it would have to be an "active list". In the Index, we would see an always updated list, with all of our current assets on the timeline (including Adjustment Layers, Black Video, Color Mattes, EVERYTHING). For quick navigation, all we would have to do, is double click on that item in the list, and the CTI will automatically jump to that items current position.
I also think the Bins in Premiere should be more like the Bins from Avid's Media Composer. When you're in "Clip View" you can sort and organize the clips in any which way that you'd like. In Premiere, you're limited to a predetermined set of sorting options.
Finally, I think in order to remain competitive, ALL of the Adobe products need a modern redesign. Premiere and After Effects (and possibly others in the Creative Could) haven't have an effective UI design refresh since CS4 (2008), the only thing that changed was the panel accents changed from Orange to Blue in color. The menu's are rather clunky and overall performance is really something to be desired on a Mac.
Premiere is the most versatile platform to edit with, but there are a lot of missing features that others have, that would greatly improve Premiere overall.