Titanic, Aliens and Terminator 2 are possibly the top, or top 5 of their genre of all time. Titanic has more competition but the scope of that movie really makes it stand out. I think you're underestimating T2 and Aliens, OP. These three movies alone catapult JC into the top tier of modern filmmakers. Also, please note Aliens was a certified masterpiece and it used mostly low-fi visual effects.

Then you add in Avatar as a modern marvel in taking a giant leap in CGI use. The guy was incredibly well rounded. I'm not sure he's there anymore but the legacy he made will absolutely last.