I believe this would be a great idea and a good boost for people looking for that next rank because it would be something they are looking forward to working towards and achieving knowing that they will be rewarded only thing is there are so many different key type chests already with most items obtainable within them it would be hard to suit this to peoples expectations of certain donation ranks because u could not just overfill the best items within the chests u have to have quite a lot of fill items or the items what are in the chests would just loose value to fast and then would just be useless after awhile