That was leaked after Magearna was revealed, wasn't it? I'd be inclined to ignore it if that was the case personally, especially with the lack of Legendaries that could represent the Sun and Moon at the end...and because I can't believe that they would ever be so careless as to allow something like that to leak. It'd be a colossal blunder.
...but then, Sun and Moon could just as easily be represented by form changes of Xerneas and Yveltal; thematically that's a tad iffy, but it's possible. So it's possible.
Some new fossils would be fantastic! A Velociraptor and Stegosaurus would be great, although I'd love to see something a bit more exotic; maybe a terrifyingly massive Megalodon, or an Icthyosaur. We've had land-based dinosaur Pokemon for a while, and a couple of air-based ones in Aerodactyl and Archeops, so how about something sea-based for a change? Well, we've had sea-based fossils, but none of them have been particularly reptilian or...dinosaur-esque.