Easy navigation through Nested Sequences.
Being able to use the 'Tab' key, or a map, like After Effects to be able to navigate from nests back to the main sequence. Alternatively, or additionally, being able to lock the main sequence in place on the left side of the Timeline. This would enable you to easily click back on the main sequence if working on a project with a lot of open tabs.
Neil Emmanuel commented
great idea. if you have multiple nests or even just want to go back and forth between the main sequence and a nest it would be really useful to have a nest navigator/nest miniflow chart...I can't imagine not having this feature in After Effects.
joseph standen commented
Not if you don't want multiple timelines clogging up your workspace. Especially with the multiple projects update Adobe have added
You can already do your alternate suggestion. Undock the timeline panel for your main sequence and put it wherever you want.