At the moment you can achieve an individual sorting of the collection entries e.g. via the number field.
But to keep the overview is very difficult. Furthermore it is very time-consuming, if e.g. an additional entry has to be inserted at a certain position afterwards.
My idea would be that you could sort the collection entries manually (like collection fields or pages) and then use this sorting as a basis for the order.
I hope it is understandable what I mean. Otherwise just ask. 
sorry for the late reply. I was on vacation during this time and thanks for your suggestion! I created a feature request ticket for it.
For everyone who wants to support this feature, please comment here with a +1 and let us know if you also have some ideas regarding this topic.
Thanks Martin!
I am convinced that would be a very good feature that would be very helpful for many applications.
Actually whenever the sorting should not be simply alphabetical or by date. → Team members, references etc.
So a clear +1 for me