You CAN'T change history - if Paul McCartney wanted to call THE BEATLES album the 'Black' album it wouldn't make any difference - It would still be the White Album wouldn't it?
Having said that, if Moz wants to re-release Southpaw Grammar with new tracks and a new cover it doesn't detract from the original - not for me anyhow...
This is basically my opinion.
A reissue can't change the original.
It may be an attempt at revisionism but it will always be unsuccessful. Fans may prefer the altered / new piece of work, or they may prefer the original. But amongst educated fans there won't be any confusion. If, against all odds, the reissued Southpaw Grammar makes a new Morrissey fan out of some teenager, by googling and visiting websites they'll quickly find out what the original was and can even seek it out at a reasonable price should they so choose.
Though I think it's not a bad thing to 'respect' the original work, more artists do that with special editions these days, so you get the album in full as it was, THEN bonus tracks, people tend to respond to that better overall it seems. But I'd stand by what I said above, ultimately any attempt at revisionism will be unsuccessful.
What annoys me more in a way is revisionism in Greatest Hits / Best Ofs, particularly when certain successful singles are left off just because the artist has a personal dislike for a track. A compilation there is serving a distinct purpose, it's a new collection. There I think the artist has more power to be revisionist and get away with it.