Big ones:
Media Management – System and Facility-wide. Media Manager should check all FCP projects on the system and LAN before deleting any footage.
Multi-seat editing – working on the same project on several FCP stations with live update of project status and smart privileges management.
Only the editor stops playback – timeline or viewer should keep playing when I switch windows, perform edits, whatever until I hit Stop or Pause.
Every frame at 2x FF and REW in the Viewer or Canvas – you think it is not a big deal, but it is. Quick Time 7 is finally capable of such a trick so we should get it.
Get rid of the stupid pseudo-overlay when capturing footage. Didn’t you tell us Mac OS X is good at multitasking?
Smaller ones:
Live Scopes – that’s what we need Core Video for, not some cheesy spins and curls at 8-bit per channel.
Mackie HUI compatibility – hardware audio faders.
Edit to timeline from Log and Capture window. With all familiar shortcuts. Option to capture right away or later. Marker shortcuts should work in L&C too.
Nit picks:
Option-Return should open Sequence from Browser in Viewer, not Timeline. There is Return for this already.
When multiple Viewers are open F9, F10, etc should work from any Viewer which happens to be on top. They look the same so the must work the same.