This is such a great question and I'm enjoying reading all of the different answers to it more than I will enjoy using that fantastic figurehead...
And there's no possible way I can truly answer this question, but I shall try...
Am I choosing an update in its entirety or just a specific part of an update?
For a specific change - I'm torn between fuses on gunpowder kegs and rowboats.
This question has really made me think back on each and every update, and how much I've loved and appreciated them all for what they delivered.
Arrgh, I can't choose just one, lol!!
I'll go with my first instinct (even though it may not truly be accurate, haha):
Gunpowder Skeletons for the fuses on gunpowder kegs alone, never mind the pesky skeleton enemy type it added for us.
(...but, really, Cursed Sails and Forsaken Shores brought so much more fun and excitement for me as well... Hungering Deep also not far behind either of those)
ALL OF THEM!!
:P