The alternate ending is the only "deleted" scene I think in the whole film that doesn't really add anything to the overall film. Aside from, as OP mentioned, it comes off a bit hokey with the super positive ending (despite Sarah clearly still hiding her paranoia) I don't think it really matches well with the overall tone and messaging of the film. For as much as the movie tries to beat you over the head with the concept that the future is not certain and the only fate is the one we make for ourselves, it just seems odd that we this binary super utopia to contrast with what we've seen with the Future War.
The rest of the deleted scenes though I think really add more context to what is happening in the film and should have made the final cut. I get that they were mostly cut for time, but IIRC, these scenes added maybe an extra 10-15 minutes on the total runtime of the film? That's nothing.