Right now the shamrocks/gems/whatever we collect are used to track our individual and guild rankings with us getting fixed rewards.
How's about, instead, we be allowed to use them to purchase our rewards?
Assign a cost to the ranking reward pirates and then let us buy them at the end of the event with our tokens, thus allowing players who fall short to still be able to burn all of their tokens to score a card they might not have been able to score, or buy two of the same card so they can evolve it into a gold.
Additional purchase items could be random pulls from the gold rescues, cards exclusive to previous events, Reese evolution cards or simply purchasing statues, chickens and kraken draughts.
Since adding new card slots is on the table then tossing them in for purchase would be a nice option as well, say 100k tokens for an extra 5 slots.