It would be stupid to make the same move twice or (three times if you include alien 3) to have the Daniels and Tennesse killed at the beginning of the next film, if there is a next film. While the prequels are inferior in my opinion, I would still like some resolution as cliffhangers suck.
Always finish what you start I say.
I think covenant actually had a rather finite ending. David accomplished his goals and won. We know where he's going, we know what he wants to do, but his overall goals, aside from the queen (which wasn't mentioned in the film itself I believe) were accomplished. He's made his decisions in regards to humanity and the engineers. He got his head re-attached, made it to paradise, eliminated shaw and the engineers, created his perfect organism, escaped the planet, and now has all the tools and human specimens he could ever want or need. He's got a ship and a wide open path to anywhere, with no chance of discovery or punishment by humanity. I think we can definitely move on from here.
I'm personally of the belief that we're just going to keep getting more of the same unless a drastic change is made. The cinema already had (and still has) the perfect vehicle for stories about rogue artificial intelligence, in the Blade Runner movies. I truly respect Scott's abilities as a film - maker and understand his desire to try something new, but this just doesn't seem to be a good fit in the Aliens universe. Fassbender is a fantastic actor, but hours of poorly written characters making bad decisions and David playing the flute, quoting poetry, waxing philosophical and kissing himself just doesn't seem like anything remotely resembling a movie that belongs in the Alien universe. Covenant just felt (to me) like a movie that was cobbled together. It just didn't seem like they have any idea where this is going. It wouldn't be so unfortunate, if not for that fact that the prequels are taking up time and money that could be put towards an actual alien movie. Sakes alive, we didn't even get to enjoy the engineers or their technology in covenant.
Maybe the different direction is a classic alien movie. Something like Alien 1979. Maybe it's another AVP set in space. Maybe it's more of a standalone creature film in the spirit of Alien Resurrection. But whatever the next direction is, I do honestly think that David's story has been well enough resolved for us to move on. Allowing David and his horrific plans to slip quietly away into the infinite darkness is a fine way to end his story, and in my opinion, a very mysterious, spooky, and effective way to do it. We'll never know the horrors he unleashed upon the colonists, but that makes it much more frightening. The whole Alien franchise could've successfully ended with the first film, it also could've ended well with the second or third film. It might not have been possible with Prometheus, but I think with covenant's ending, we've made it to a point where it's creatively feasible to pull away.