@Dukesky - you didn't make it to the end of my post (yes I agree that current keys should be x4 with the update)
Generally now people don't solo Shadow lairs because the payout isn't worth it solo - it is worth it if you go in a group. In which case you're splitting the cost anyway and only paying 450CE. So the payout wouldn't have to change at all because it would be the same 450CE to payout ratio.
I haven't played a Shadow Lair yet, so I don't know their payout
(would their loot have to be lowered since there'd be more players soloing Shadow Lairs?)
If this happened: Players with old Shadow Keys ought to receive x4 keys for every unused one they have.