I totally agree with the extra seafood and the negative side effects to eating raw meat and drinking salt water. I'd personally say that eating too much raw meat or drinking too much salt water would make you vomit (gross, but fairly realistic). Also, it's worth noting that drinking salty beverages will make you thirsty again quicker (hence one of the reasons you have to purify the sea water (there are other reasons like fish poop and bacteria and other gross stuff, but whatever)).
As for the day/night cycle, it looks like it's on the way!