Perhaps there could be some kind of semantic syntax that would group together the factual claim and supporting information (data and references). For example,
<"e=mc^2",cite1,cite2,data1,data2>
The claims still could be included in prose, but also easily extracted, analyzed, manipulated, etc.
With a little work the claims could form a semantic web, with all that entails, and the validity of cites could be checked automatically when the document is opened or on a regular basis, updating the claim appropriately. For example, the UI could display the claim differently based on whether the cited source has been withdrawn, partially invalidated, superseded, confirmed, rarely cited, heavily cited, based on impact factor, if the source's own citations have been invalidated (e.g., claimC cites claimB which cites claimA; if claimA is invalidated, there should be some sort of indication in claimC -- consider that the invalidation of a seminal claimA would set off a massive chain reaction, as it should), etc.
But that all seems obvious and I suspect I'm not the first to think of it.