Instant preview of Sequencer operations

In the 3D View you edit directly on the visual representation, however in the VSE you edit sequences which are abstract illustrations of a result only visible when playing back in the VSE preview. Many of the VSE functions are the same as in the 3d view for consistency, but in the Sequencer you do not get the a/v feedback of what you're actually editing as you edit.

What is missing is a visual preview when you're ex. trimming, moving, slipping and sliding video.

In this example the playhead is moved to the first frame of the strip as it is trimmed. It would be better if the playhead wasn't moving, so when finished trimming the preview would return to showing the frame position from before the trimming started: Youtube - instant preview of VSE trim