You're right. He has nothing left to prove after Alien and Blade Runner. All other movie's Ive seen of his prove that he's a perfectly serviceable director. I think I'm in the minority but I even really enjoyed The Counselor. I guess Prometheus left a bad taste in my mouth, which might be more Lindelof's fault.
Damon Lindelof has said that most of his job on Prometheus was to take dictation from Ridley on the changes he wanted to make to Jon Spaihts' original script (which was a direct Alien prequel). I actually wonder if the reason Ridley's films have been so patchy in recent years (haven't seen The Counselor so can't comment) is because he's been taking a crack at the storyline. He didn't have a hand in it for Blade Runner as far as I know, and certainly didn't for Alien.