Although in this instance "The following are" actually sounds fresher and more authoritative to my mind. But even that aside, when shifting the subject could undermine the original emphasis or context such as countering an assertion that there were few or any unratified treaties Japan was a party to, I personally wouldn't take the liberty. For what it's worth, neither would I change it to 'Japan,' since that's the only country it could be referring to.
Filling in the gaps for EDICT is a good idea. I've stumbled onto a handful of terribly ungrammatical English sentences and simply never done anything about it.