Interesting that you bring this up. Part of me does like the timeline but the other part does not. Tracks are better, just my opinion.
Now that I am off that tangent, any editing software would greatly benefit from how Final Cut Pro does organize clips. The last major update was a huge improvement. Avid is a bit clunky when it comes to importing clips into a project. I have not used the latest and greatest version of Premiere Pro since it is subscription only. I will say it is easier to import clips in there.
One thing that Apple should bring back is storyboard editing. With the previous version, one could arrange clips in a certain order, drag them over to the canvas and easily make a rough cut within a few seconds. Premiere does the same thing but it is called something else. Not sure about Avid having this feature.
On another subject, but one that is related: Adobe should look at adding a group like feature much like Motion has. I know that pre-comps are often necessary but having to switch between comps to make a change then back over is not exactly efficient. Easy to do but efficient it is not. Motion could likewise benefit from having the ability to parent layers, have a null object and expressions. Then again, editors are the target audience.