1st. Story.
What you came up was ok but not good enough. I enjoyed miniquest with tracking mode taken from witcher game. But… you have lost a potential minigame… you already have snowpang… and players of witcher know the quest when we fought Ciri as Witcher in snowball fight [ lost potential for a fun game that you already had mechs for ]. You could also make a fight with an enemy from witcher world… so much lost potential. Geralt, triss, ciri, yennefer as siderials for some interesting event dungeon… You really dont care and dont know how to use your imagination.
2nd. Skins…
Really… like really… Witcher and Ciri skins are nice but you left out 3 other characters… look
Those could be nice skins for the characters to enjoy. Even the Dandelion one [ witcher worlds version of mokoko lol skin ]
3rd. Potions. Those are not op but interesting. Why not learn a recipe to craft them ? Sth simple because of low benefits. People could make them for lols and gigles.
4th. Vendor. No vendor on the island ? Why? You could have always made some witcher coins or sth like that exchangable for pirate coins or some potions or some battle items [ this would be best as witcher world is full of alchemy and could have their own version of our destro, sleep, whirlwind potions ].
TL:DR
Use the opportunities better. Event could be a lot better and interesting. You have missed a lot of potential here, but you could always use this event to be repeated and improved. More skin options = more money. A little fun = more attached to the game despite boring 2x chaos 2x guardian per char daily chore. [ make it 1x god damn it ]. You can make those interesting with quite low effort [ all i mentioned does not require any new mechs ] but you choose to just brush us off… why ? I like the frame of the game and many players do. Do not punish us for playing it like this.