I don't know what to think about it all. Isaac can now crouch; evasively roll to the left and right, and use cover. Also, you won't only be fighting Necromorphs this time around, heavy armored humans as well, though these enemies will, or can become Necromorphs. I have no idea how adding another character to the main story could work in congruent to the single player campaign, I mean, how will it make sense? I am cautious, but I really do enjoy Visceral's games, and have no reason to not have hope. These are only a few of the new things that come with Dead Space 3.
I love the Dead Space franchise, especially the first two main games, and I hope three turns out to be just as good, 'cause it seems like they're really trying to adhere to what they believe the big market loves. Does this mean we'll be getting Dead Space 3 as early as next year? It took almost three years to get Dead Space 2 out, so this just seems early, but as I said, I hope it's a great game like the first two. Anyways, if you haven't read it yet, and would like more details, here's an IGN article for you to read that kind of states what I had said, though co-op included.
Edit - About the co-op, do you think this means it's just some random guy beside Isaac, a new character to Dead Space, or could it be Ellie Langford? Could there be some Resident Evil 5 inspired gameplay in there? I don't think I'd be entirely against that choice of style.
Edit - Oh wait, I forgot it said it was a man with a scar on his face that is used to guide Isaac.