You thew out two example that have more than one remake!
If you meant THE THING 1982 is better than the 1951- well, maybe (probably), but so hard to compare those eras so far apart.
THE THING 2011 better than either of those-
PLEASE....
INVASION OF THE BODY SNATCHERS 1978 was just as effective as the original 1956 and really pushed the paranoia level up a notch. Abel Ferrarra's BODY SNATCHERS (1993), and Oliver Hirschbiegel's THE INVASION (2007) remakes were straight up dog poo.
And I agree that remakes don't 'erase' the originals- but unfortunately, when these flicks get programmed on whatever channels in the future, they will most likely go with the remake and not the original (which is really sad- cuz that means that Sam Raimi kinda inadvertently screwed his own movie getting more views).
I'm of the ilk that believes you should remake films that were 50%-75% there (good ideas) and just couldn't land it, or had a bad script, or not enough money, etc. (For me examples would be: EVENT HORIZON, SPAWN, HELLRAISER II (<------using your horror movies theme)).