Honestly, I think Scott is too big for these films. Alien was great because it had such a great collaborative creative team on it. People don't tell Scott no now and Scott tends to bend to the studios (*cough* Alien inclusion that felt forced because it was *cough*) because he knows how to play the game to get what he wants (David).
While I like David, I'd still a rather rounded out finished production. I think it's time we got back to new faces.