I think this is because the lawyers were co-ordinating their arguments, so as not to repeat each other. It doesn't make a whole lot of sense for there to be two separate appeals saying the same thing. This is my impression from reading them, anyway - even where they deal with the same issue, they do so using different arguments, different quotes, etc.
I would feel a similar relief if there were some crucial bit of evidence which emerged to prove their guilt - that would certainly be preferable to two innocent people being locked up. I find it odd, though, that you seem to be looking for something conclusive to unequivocally exonerate them... Shouldn't the emphasis rather be on whether or not there was proof beyond a reasonable doubt, not on whether there's rock solid evidence they didn't do it?
But what literature are you talking about? I've been waiting for ages for some evidence to emerge which contradicts what Kevin_Lowe and LondonJohn have been saying, but I haven't yet seen any: so far the closest thing has been Machiavelli's cite that after an extremely large meal (1000+ calories) it might take as much as five hours for 40% of the gastric contents to empty. But in this case, we know on the one hand that it's highly unlikely Meredith ate as much as that (unless she pretty much ate the entire pizza and apple crumble herself...) and on the other that her stomach hadn't even begun to empty. Another abstract cited by someone suggested "an unacceptable degree of imprecision" using stomach contents to determine time of death. Well yes, probably that's generally true, given that you can only estimate T.O.D. to within 3-4 hours, which is fairly imprecise. But not in this case, as has been said over and over again, because we know Meredith was alive for the first three of those hours.
Personally, I think all the other judges (aside from Massei) plus the coroner were not too far off the mark: an estimated T.O.D. of approximately 22:00, +/- an hour. Given that it seems the meal was over at 8, while Matteini at least bases her estimate only on the fact it finished before 9, I think the T.O.D. can be moved back further to at least 21:45, with the fatal wounds having been made at around 21:35 (both +/- an hour, of course). Using this logic and combining it with the fact there were people outside the cottage gate from around 22:30-23:30, the last half hour of this time span can probably be ruled out, meaning death must have occurred before 22:30.