Can anyone explain the way they'd like to use this feature to me? On the one hand, if I was going to move the tracks around vertically I would expect mouse dragging to be the most obvious way to do it, but on the other hand I can't understand why anyone would ever move the whole track unilaterally with all its clips across an entire sequence and have the stacking order of which clips are visible when completely changed let alone any and all effects involving masks or track mattes or transparencies of any kind.
I'm trying to imagine even the simplest timeline with only two tracks that's only a minute or two long and has no effects. In that scenario I still can't see how the effect would be any different than switching off the top track using the 'eye' icon. For anything longer and more complex with more tracks, I can't figure out a situation where it wouldn't be a disaster for the timeline. At least if the results were bad it'd be a quick an easy fix to just move the tracks back how they were, since nothing's overwritten or destroyed, but again I can't imagine why you'd move them in the first place.
I'm totally for improvements. Why would this be good to have? I think of a documentary of 1 hour length, if I would move 1 track everything will change (transparency will not work as it did, tracks with shots will be covered with other shots, it would be a mess)