We have all experienced that moment when we have spent hours working on a composition - making it perfect... only to realize that we forgot to include something in the sequence. I unfortunately can say this happens to my team regularly.
If we try to move things in the sequence to make room (perhaps we forgot to record the intro or a speaker talked over one another) then we are in for a HORROR STORY because now everything in your Composition is misaligned... the timestamps/highlighted text of comments and the splices we made in the composition view are no longer accurate... and we must either revert to an old version or cry as we attempt to fix the mess we have created.
This could be solved by creating an additional tool in the multi-track sequence editor... that would act similar to the "Wordbar" feature in the timeline editor so that you could move all the tracks in a sequence to make room for the modification that you are about to make. This would need to work in sync with the existing compositions so that splices and timestamps can stay exactly where you intended to put them!