well, i look forward to someone taking the initiative to do so
i for one, feeling comfortable with the rules as is, can imagine myself missing SOMETHING in the 3.5 books, just because i probably won't read every page line-by-line to see what the changes are. heck, even in 3.0 i still find myself missing important rules because i happen to skip 1 particular line when scanning over the book.
i can imagine certain sections of the 3.5 books may not be that different from 3.0. on the other hand, what about spells? i can imagine that more than 1 or 3 are probably gonna be revised for 3.5. that being my assumption, i cringe at having my 3.0 phb next to my 3.5 phb and going spell by spell to see if there is any change (not that i would actually do that, but if someone else would and let me know what they find...) i think the same could be said for magical equipment, regular equipment, almost anything in the book for that matter
that being said, hopefully someone will take this little thought into their head and start making plans on creating a master document for the differences between 3.0 and 3.5
in regards to the SRD, i've only looked at a few times so i'm not really familiar with the whole updating process, even if it is updated, would the SRD explicitly state that [this has been changed in 3.5] or something like that? when i think of the SRD being updated, i just assume that it will be in the same format as the current SRD, with no way to tell what has been changed without having to read over the entire document, which i would rather not have to do.