Welcome newguy! I would suggest adding a bandanna. It has a multitude of uses, water pre-filter, dust/smoke mask, pot holder for hot items, head covering for keeping sweat/hair out of face, bandaging, etc.... If its too big for your kit I'd suggest to throw one in a pocket.
If you are looking to upgrade the ziplock baggie, Glock-a-Roo in his thread "interesting water container-Aqua Pouch" has found a fine looking piece of kit that does away with the "cap won't allow me to fold it flat, it takes up too much room for a small kit" problem.
Now for the abbreviations.....
DD=dear daughter
DS=dear son
DW=dear wife
DH=dear husband
EDC=every day carry
BOB=bail/bug out bag
SAK=swiss army knife
FAK=first aid kit

-Bill Liptak
P.S. There are others, lemme know if you need one translated. I'll try my best though there are a few I'm clueless on