Well honestly packaging the new game with the first one might not be a bad thing. Also getting a better writer (ie no military ships getting overrun by single opponents when it's highly improbable to say the least), working out some of the details (ie no 4th wall breaking shops) would also be good.
Truthfully though I suspect part of what killed Dead Space was simply the economy. People have been being attracted more to sequels I think because they know what to expect when money is tight. Add to that the relative length of Dead Space (it's not exactly a long game, nor a sandbox game you can put hundreds of hours into) and you can see some of the obstacles it was dealing with.
Personally I welcome the Action/Horror Franchise and see it having a lot of potential and questions to answer. I will also say that while the movie blew chips (I assume they didn't really talk to the game writers much) some of the other add-ons like "No Known Survivors" were pretty good.
As far as doing a movie, consider that this game is pretty much a homage to (or rip off of depending on your opinion) the whole sci-fi "horror on a space ship" genere. You basically had hallucinegenic "Event Horizon" type stuff (albeit not caused by demons), the expected creepy monsters to shoot like from "Aliens", and a *possibly* malevolent (though in this case more likely to be benevolent) Alien Artifact like in "Supernova" (Supernova being a "D" grade movie where the gimmick is that there is an alien artifact planted by another civilization that is actually a mega-bomb designed to be uncovered by civilizations once they reach a certain point so they will wiped themselves out, removing the potential intergalactic competition before it can truely get started... a variation on the basic concept of the original "Species").