I don't have any hard evidence for this, but the fact that they keep calling it "remasters" seems to imply that they intend to keep the games as close to the originals as possible, at least in terms of gameplay and whatnot. Since they're reportedly being built from the ground up (which is really the only way they could have done it), and since they are exclusive to the PS4, I personally think the graphics are what's going to change the most.



It just makes the most sense to me - this is meant to be a nostalgia trip, but most people wouldn't want to play the games with PS1 graphics on the PS4. They'll probably address some of the flaws in the older games like the save system in Crash 1, but I wouldn't count on too many changes besides the graphics.



But that's just my guess anyway.