I think there's a threshold for how often a remake is needed.
There are a lot of people that never played Resident Evil 4. It was like, old school PlayStation. The remaster was substantial and not only completely changed the game, but also brought it to a whole new generation.
Dead Space was just a cash grab and the old game was fine. I never even considered buying it.
Just like all games: vote with your wallet. We don't have to buy absolutely everything that gets released.