So before anyone accuses me of whining I have just about every item the game has to offer and definitely everything I'm suggesting they bring back into the game for purchase.
So I think Rare should start reintroducing a number of sets that had pieces that could only have been attained by spending Bilge Rat Doubloons earned during certain adventures. Especially the ones that are part of a set and have items in the stores such as the Bone Crusher, Wailing Barnacle, Forsaken Ashes and Mercenary items. A new player might have hopped in loves the Forsaken Ashes set and then is disappointed to find out they can't get the guns and ship set, or they buy the Bone Crusher items from the clothes shop and find you can't get the Hat, or Jacket/Dress.
I was thinking that these items especially after a year since they were first and last offered should be placed either in the regular shops, or permanently in Dukes Shop as something players can spend extra Bilge Rat Doubloons on. Maybe make a requirement for buying them the completion of the original event commendations. For example you need to sit on all the Skeleton Thrones to get the Bone Crusher Hat, Jacket, and Dress. Players can get a few months of having the item exclusively from an event especially if it's part of a larger set, but should ultimately be reintroduced so other players can get them and complete certain cosmetic sets.
To all the people moaning about how the items need to remain exclusive because they want to feel special cause they have something other people don't all I have to say is that it's a petty and selfish excuse. The commendations and things required to obtain most of these items are still available to unlock. Nobody would be working harder to get these items and arguably even harder since many of the earlier ones had no unlock conditions and you could get if you had the spare doubloons from the last event to get them.
Now obviously certain items shouldn't return and should remain exclusive to show you participated in certain events, or were in the game for a while. The Founder Sails you got from playing the Alpha, The Hungering One Figurehead from The Hungering Deep and the Three Region Sails from Cursed Sails should remain exclusive because they specifically showed you participated in certain events. The Festival of the Damned Face Paints, Sails and Lantern can remain exclusive, but I think they could be offered around every Halloween for a limited time. Actually one thing that could and should remain Exclusive from each event is a title showing you participated in the original event.