If everyone kept kosher, there would be far fewer pig-experience-moments than the current world, including much less pig-experience-suffering. Is that good or bad for someone who values pig utility?

I value pig-utility. I'd much rather see a smaller number of comparitively well-kept, well-treated farm pigs and a healthy population of wild boars than the status quo. I'd also rather not see that arrived it by a mass slaughter of all other pigs, though, and pragmatically I'm not going to get that either way, so "a largeish-but-not-contemporary number of reasonably well-treated pigs farmed for food production" would be a much more feasible goal. Temple Grandin does a lot of work in this area, actually.