This request has been (mostly) implemented in Obsidian Release v0.12.0
There are now hotkeys to show the panes for file explorer, backlinks, outline, starred, and tag pane.
These hotkeys can be set according to documentation: Setting hotkeys
In Obsidian → Settings → Hotkeys they are named as following:
Search: Search in all files
File explorer: Show file explorer
Backlinks: Show backlinks pane
Starred: Show starred pane
Outline: Show outline pane
Outgoing Links: Show outgoing links pane
I do not use tags and I could not find associated command to show tags pane. Could someone confirm this is still missing or can this request be archived?