I would like a keyframe track which shows all the keyframes in a layer in a single track. All selectable and moveable.

This is fairly common in 3D programs and is a good way of moving a lot of keyframes without having to reveal and select them all individually. Often times in revisions it is necessary to move large blocks of keyframes as a group. This would make that process much easier.

This already happens to some extend when there are a number of keyframes within a collapsed property (transform, contents, etc), but it's purely cosmetic for reference. They can't be selected, moved, or snapped to.

I personally am not looking to use this to edit individual values, just for bulk moving or scaling keyframes in the timeline. Leave a comment if you feel differently about that detail.