Automation inside editor view, with multiple lanes possible to view side-by-side or layered on top of each other, with either MIDI or Audio (with some degree of control over transparency of the layers so it is clear which layer, and thus event, you are editing, and which others are concurrently visible and/or audible).
More to this point, greater flexibility in Editor view with displaying multiple MIDI and or audio tracks (Bitwig Studio by comparison does this quite neatly and cleverly).
I should be able to select multiple events in the Arranger, and if I have the Editor open they should both be visible and editable, and;
If I have the Editor timeline synced to the Arranger, and the events occur at the same time, I should be able to edit both at the same time according to the Arranger timeline;
Conversely, if I select both and don't have this option selected, I should be able to do this editing, via the Editor's sequencer, thus permitting me to make edits to one of more non-contiguous events, even if they are on the same track (some option like "Sync Event Start" might be necessary to enable this).