I've never had a problem with setting an Alien story on Earth (even with the AVP movies), though honestly if they were going to do that I'd prefer they just went all-out and did an Earth War-style thing that could really show just how bad things would be if they finally made it here. And I certainly don't have a problem with moving away from David as the creator.
The thing that makes me go "ehhh" is that, by setting it prior to the original films, you're limiting yourself unnecessarily both in terms of the continuity you have to match up with and thus what you can ultimately do, and also in terms of how you can surprise the audience. Because, as has already been mentioned, no matter what happens in the show, we as the audience are going to know that ultimately it's all going to be contained somehow, and that it's going to end with the Alien still not being common knowledge to the general public, because that would literally undermine the entire point of bringing Ripley along with the marines in Aliens if it didn't. And that's not the sort of "minor continuity issue" they could just sweep under the rug.
Set it after Alien 3 though and you've got no problems on that front. Want to have the story go in a direction where the general public becomes aware of the Alien? Sure! Want to have them get loose and swarm all over North America, or at least imply that that could happen and make the audience worried about that possibility and those stakes? Go for it! Frankly I doubt maybe people would be as annoyed at possibly retconning elements of Resurrection than the entire original trilogy (and even there they imply that Earth is a complete mess for some reason, so there's still some wiggle room there if they went that route).
Do that sort of thing pre-Alien though and we're not exactly going to be shocked if it all ends with the major location the show is set in being nuked and/or everyone except the Company folk being killed off in order to cover things up and match it all up with existing continuity.
