Honestly, the Estate should stop linking things to anniversaries. Don't be beholden to that criteria. Just pick an album that you think is worthy of celebration and celebrate it. No need to say, "We need to do something for this anniversary!"
If they don't put out a HIStory 25 this year, I'd like to see a HIStory: Book II next year, with the first disc featuring the 1995 album and the second featuring new material from all eras. That way we can get rid of the boring "greatest hits" package, celebrate the criminally underrated original album, and get a new album out of it. Two birds, one stone.