There's no better person to revisit the Alien universe than Ridley Scott. The only man for the job.
And his career hasn't been diminishing returns. He started off with a great film and then created two out and out classics of cinema. He then made a long line of fairly standard but stylish thrillers through the 80s interspersed with more interesting films like Legend and Thelma and Louise. None of these films are poor in my opinion although they are not landmark films. He then continued to make decent but workmanlike films until he hit his stride again with Gladiator. Black Hawk Down was a good film and personally I preferred Hannibal over Silence of the Lambs. Kingdom of Heaven was a quality film and as I'm not prejudiced to despise a film just because of Orlando Bloom I didn't find anything wrong with it. I haven't seen Robin Hood, or in fact all of Ridley's films but I have no doubt that I would find them all perfectly acceptable. However the exciting thing about Ridley returning to science fiction is that he is clearly at his best when he is being creative, and historical and futuristic worlds bring out the best of creativity in him because he is basically visually constructing everything, not just lighting and composition.
Recent hints suggest that Prometheus has stronger ties than the news stories of a few weeks ago implied, but even if not, this is still likely to be the most interesting science fiction film in a long time, hopefully with a maturity that really interesting sci-fi used to have. The fact that it has expanded beyond the obvious restraints of a prequel means it must be strong on script and not just ticking the expected boxes of every other sequel/prequel that Hollywood churns out.
Oh, and why should we discuss this film on this forum? Well, I don't know about you but I can already see stronger connections in this film than I ever saw in Predator. I come to this forum for Alien (because it's one of the best places to discuss the film), but AVP just isn't on my radar at all. Whilst speculation for what Prometheus actually is remains this is a perfectly valid place to discuss it.