I am very tempted in my run of the AP to change the Ability damage from CON to INT and Dex. So Instead of the RAW 1d4 con, I would do 1d3-1 INT and 1d3-1 Dex. So instead of the rum killing you it simply takes the edge off your reflexes and makes you a little less of a critical thinker thus more dociale or easy to control.
I think this would encourage the brutish less intelligent PC characters to swig with the best of em and become right pirate brutes. While the more intellecutal or nimble characters will will try to once in awhile dump their rum so as to keep their wits about them.