In that book, a man, George Orr, has "effective" dreams, which can change the world. To begin with, little things happen. He imagines the wall decoration of his psyschiatrist, Haber, is different, and it becomes so. Haber becoms aware of the power, and directs Orr on a series of dreams to eliminate the world's problems. These wishes are seemingly fulfilled by a Literal Genie. He eradicates racism by everyone becoming a monocultural grey; overpopulation by a plague; and causes peace on Earth by an alien invasion. The original timeline is thought to have had a nuclear war. Better George Orr than that, though.
X-Men/Alpha Flight covers similar ground. A geological research expedition has chartered a plane, piloted by our Madelyne Pryor and her husband Scott Summers. It falls into a situation set up by Loki, who is trying to curry with Those Who Sit Above In Shadow, which are some kind of metagods. Loki has set up a sweet fountain from which the unpowered people get powers (Maddy becomes a healer named Anodyne; Cornucopia can provide for their material needs and so on). Anodyne fixes various Alpha Flighters and X-Men of their problems - Rogue and Scott gain control over their abilities, Aurora becomes more stable, and Wolverine becomes a man. (Happily, this does not seem to include whatever is troubling Northstar - that's society's problem, not his.)
They are initially quite taken by the idea of fixing all the world's ills through powers (partly direct - but also the notion of forcing everyone to have powers will remove their prejudice), and don't wholly reject it when part of the price - the death of magic - is made clear to them, despite the chance it will lead to the passing of Michael and Elizabeth Twoyoungmen (Shaman and Talisman). But they've obviously not been keeping up on their Alan Moore, otherwise they'd have remembered that art is magic. Faced with a world without creativity, they don't see that there's much of a choice, and spurn the "gift", enraging Loki, and causing him to vow his revenge upon the X-Men.
I did this series now as this is when the Chronology Project reckons it happens, but in fact, it was published a bit later. This is unfortunately timed, as Scott will go from learning the news about the pregnancy (in December 1985) to abandoning his wife and child for his dead girlfriend two months later (in February 1986). Still, despite the oncoming tragedy, there are good moments for Scott in this with Rachel, who is still slowly coming to terms with being in the wrong past. She doesn't quite acknowledge Scott is her father, but it seems he knows it anyway. Let's see how long they milk that one for.