If we got a leak back then we could get a leak again, but if we don't get leaked this time we may end up not knowing the evolutions until release day, meaning that they'll actually be secret for once, at least to those wanting to go in blind.
However, I recall Serebii was threatened when they leaked the entire new Pokemon list for 5th Gen around the time BW was about to be released. 6th Gen we found out the rest of the new Pokemon by people leaking in-game pics on the internet caused by some countries breaking the street date (and people likely speculate it as the reason EU is being delayed with the release of ORAS and now SM). The question is, what leaks could we get for 7th Gen during the final days before game release?