I agree with JD, Live Magic has had its place in the Queen canon superseded by two full Wembley releases, the latest one being the best edition, with the full version of "Tutti Frutti" and bonus tracks. Live Magic is more of a Tour Highlights type of collection (it's got tracks from Wembley, Budapest and Knebworth), though less impressive than Live Killers, since it's only one disc (59 minutes vs 90 minutes). It's in a tough position, because discontinuing it doesn't seem to be Queen's policy either, and that's fair, since it was an original release, part of their original catalogue.
It's hard to say what they should do with it. One option, leave it as is, but don't be surprised if fans aren't too thrilled about buying it again with nothing new on it. Another option, add more tracks, fill it up to 80 minutes, and hope the fans don't mind having two Magic Tour live albums that are nearly identical, with some the same tracks on both (like "Hammer To Fall," which I believe is from Wembley). Third option: couple it with a new live album, such as the Rainbow '74 SHA Tour concert. Last, least effort needed option: collect the odds and ends live B-sides floating around and put them on as bonus tracks. They'd include:
Stone Cold Crazy (1974 The Rainbow)
My Melancholy Blues (1977 The Summit)
Rock In Rio Blues
Love Of My Live (1985 Rock In Rio)
Under Pressure (Knebworth Mix)