For me Aliens isn't on par with Alien.
Alien is a masterpiece. It is up there with the great classics.
Sure aliens is a great movie, but it hasn't the great artistry that alien has.
But, Cameron hasn't directed a bad movie for about 30 years, the man knows how to tell a story.
And even if the story isn't that great or has been told before, like Avatar, he knows how to deliver a thrilling ride. He knows what works for the audience and what doesn't. He is a scientist of movie filmmaking.
Ridley has a lot more bad movies and failures than great one's, it's like he doesn't knows what he is doing all the time and works on a whim.
Prometheus and Alien Covenant are bad movies with great ideas.
They have problems that could have been very easily been fixed by an average director.
I don't know how Ridley managed to make a movie as bad as Covenant, maybe he was his intention to end the franchise. Who knows...