After using iMovie 08 (7.01) I have these observations. Fundamentally it's a workable app with a nice library section. But... But little things don't ring true for a contemporary Apple app.

Sloppy and confusing naming protocol - iMovie 08 (7.0)

The inconsistent and pessimistic default file name/location protocol...
iMovie 06 - My Great Movie/Movies
iMovie 08 (7.0) - My First Project/Documents

The User Interface is overly complicated. Each of these items should be achievable in 1 action.

Clip Trimming - Now takes 3 actions - Drag Selection/Trim/Confirm
Clip Addition - Now takes 2 actions - Drag Selection/Add
Audio Levels - Now takes 3 actions - Select/Amount/Comfirm

Aside from the obvious differences between the new and the old versions, the main downside to iMovie 08 (7.0) is that it's not actually quicker, easier or more intuitive to use, because seemingly simple actions take numerous steps to achieve.

My suggestion to Apple would be to..
- Fix the UI in iMovie 08 (7.0)
- Blend the two apps with a Basic/Standard/Advanced option.

To me, iMovie 08 looks and feels like an outside consultancy job, or a repurposed library management app with basic editing functionality simply stapled on the bottom.

Wait for the rebuild.