[Adanadhel]

If Sauron recovered the one Lorien would certainly fall (all of ME would.) But if the one was lost again, or was destroyed she could have used the Elessar to maintain the magic of Lorien, just as she did in the second age, when the elves had to hide their rings.

This always bothers me... she should have kept the Elessar and the elves should have stayed in Lorien.

If there were implications for Aragorn not being able to become king without the Elessar, she could have just loaned it to him until he became king. (I know, all just wishful thinking... and certainly the Rivendel elves would still have left.)