In my opinion, anniversary items should always return in anniversary events (the previous ones with a lower droprate, to maintain a considerable value).
About items that can only be obtained once, well, it's painful to say, but it's a little unfair, as they come in specific missions, and are difficult, having to have a team of 3 or 4 players (final destination ttf), you don't know how much it hurt me not to get the items because I didn't have a team to play with.
Although my vote will be for the items to return at another time as a continuous drop, I would be happy to know that those who can't get them this year will be able to try next year, or buy in the meantime from another player, making a very rotating market. My fear is that the items on this server will end up having an ending like the previous one I played, where in 7 years I never managed to have 1 pgf, or weapons with hits, due to the values of impractical items, for example (1 pgf cost 300 to 500 dts)
A beautiful example of this is the Christmas Spirit every Christmas we have the chance to catch it, wings of life, valentine wings at the Valentine's Day event, and so on. But anyway, I don't know what the central idea of the server is, giving everyone opportunities or having players with unique characters (which isn't all bad either). Whichever option wins, here will still be the best server.
PS = magic if you have 2nd anniversary wings sell me one!(desperate emoji here)
PS 2= I couldn't remove the bold text