I think Titanic, because it is so popular, has gone into this realm of iconic film where it's really easy to sort of mock the film instead of take a step back and judge it on its own merits.
You know, how people view it in chunks? "I'm King of the World!" The spitting scene. The Leonardo DiCaprio frozen scene. The drawing Kate Winslet's tits scene.
It's a series of little gags now, instead of the unexpectedly high quality movie about the Titanic's demise with the cutting edge technology that was used to present that horror.
That said, Cameron does have to do something about how cheesy his movies tend to be if you take a step back. I think the word is... a lot of his films aren't "timeless" so much as spectacles for its specific era. I have a real problem with the scripts he makes and the way he often directs his actors. I like Cameron but this is what prevents him from being a truly great director, imo. But unlike some people, I only think Aliens still holds up well today... Terminator on the other hand... eck