First: It is of rather little importance to me how this day is celebrated, as it is just this one day. Unless something utterly preposterous is done, like having a day when danger does not drop when you are plundered, this will hardly affect the game much.
Secondly, my initial post was not really meant as "since pirates lose a day of plunder, they should get something in return". That was just flavor text for my suggested "Plunderfest". Again, this was just one day, and hardly affected anyone much.
It is far more important to me how the game works the other 364 days of the year, than how it works on one specific "special" day. I want more action in the game, but that needs to come due to altered general rules, not due to one, particular day.
So. Having stated that it's not really important how this day is celebrated, let me still argue for my suggestion. While I do not think that pirates need to "get back" what they lost during the server migration, as they hardly lost much, it so happens that the other "special day", Kaptains day, favors merchants greatly. A pirate does not need more than 200 captain, and he can get those from stealing ships. Thus, one free captain has really no value. A large merchant, however, one who is above the bribe threshold, will need to use three bribe cards to get one extra captain. At the current market, that's around 40 credits. To medium sized merchants one extra captain has less value, but it is still worth over 3,5M gc to a merchant with 500 captains. So it would hardly be unfair if this new special day came with an advantage for pirates only.
Also, Kaptains day comes and goes with nothing really happening. Everyone gets a captain, but the game goes on as always. I would like this new day to have an element which sets it a bit apart, that makes something happen in the game. Reducing the cost of plunder would probably achieve that, by causing more plunder action in all ports. The "cage fight" suggestion by Will would also set the game apart, but personally I never saw any fun in showing off the ships one has in the marina, with no effect whatsoever on the game once the day is over. It's the things that affects the game, risks with potential benefits, that are fun, in my opinion.
This sure was a long post to discuss something which, as initially stated, really is not important...
