I don't know if I think the alternate plot ideas from Sullivan are better, but I think they'd all make for wonderful storytelling as well. I often think that it's not what your show is about that makes it good or bad; it's how it's about it. There are a lot of ways to put these kinds of puzzles together, and sometimes I'm left thinking that one version or the other isn't better or worse, but has different strengths and weaknesses, and that it really all depends on execution. I think I would have loved Sullivan's version of PIC, but I also loved what we got.
I do agree that Elnor, the Artifact, and Seven are insufficiently well-integrated into the finale. I think that all three of these elements resonated thematically with what PIC was trying to do, but I think that that thematic resonance would have worked better if they had been integrated into the finale better.
My personal preference? The Artifact is back into orbit; it's holding the Admonition-Makers off, but only just barely. Jean-Luc needs to get Soji to close the portal. He does, the same way he does in the actual show (God do I adore that "That's why we're here: To save each other" line). The Romulans skiddaddle. Then, while Jean-Luc is on a four-way call with Riker, Seven and Elnor, and Soji -- it happens. He collapses. Jurati scrambles. Seven intervenes. Connecting with the cube and becoming Queen means she knows of a way to save him. But it means fusing the golem Alton is working on with Borg technology -- something Jean-Luc might not agree with. Riker, Seven, Jurati, and Alton aren't sure what to do. When he wakes up, Jean-Luc does not look Borg -- be he has some of the parts inside him, fused with the golem android tech. He freaks out at first; how could they do that to him? How could they put nanoprobes in his body, how could they use Borg tech to transfer and house his consciousness? But then Soji and Elnor convince tell him, it was them. They convinced Jurati, Seven, and Alton to do it. Jean-Luc, you see, after all these years alone, alienated from children, never able to hold down a relationship, unable to build that family the Nexus showed him he secretly wanted, has a family now. He has children. He is their father, and they need him. So, for their sake, Jurati, Alton, and Seven gave Jean-Luc a second chance at life. He can end it if he wants; no one will stop him. But Soji doesn't want him to. She says to him: "But you know this isn't why you're here. You know the real reason: we're here to save each other." And Jean-Luc realizes he can't forsake his family a second time.
I think that would have given Elnor, the Artifact, and Seven a better resolution than they got, and would have provided greater thematic unity to the story at hand. But -- hey, I came to this after thinking about it for two months, without the pressure of a tens-of-millions-of-dollars production breathing down my neck. Hindsight is always 20/20.