For the collections that I have made so far, I think it makes sense for the most recent videos to be at the beginning of the collection. Whenever I add a video however, that video is added at the end. It is very inconvenient and time consuming to move large amounts of videos to the top of the list by dragging them.
It would be nice if the default behavior could be changed to add videos to the beginning. Or perhaps an option to sort a collection chronologically ascending/descending... Or perhaps an option to move a video to the top or bottom without dragging it.