I'd like to see this one, also, but it's Warner owned and they have thousands of titles in the vault, so I'm sure many are ahead of this one in the restoration queue for Blu-ray release. Additionally, it's dependent upon the quality of the existing elements and the cost to restore them. Warner Archive won't release films on Blu unless they look and sound as pristine as possible and make sense financially.
Although you never know. They've released a number of titles from out of left field over the years.
The film may not be very dramatically sophisticated, but Debbie's singing is the best she ever did in a film. I played that soundtrack LP to extinction back in the day (also loved the piano solo that ended the first side), The Movie does feature great supporting players: Greer Garson, Agnes Moorehead, Ricardo Montalban.