Weren't the original film masters partially eaten by rats or something?
So unless those rats were DS9 fans... it just looks like bad luck.
Also if they are ever going to do a remaster like TNG-R, they will also need to redo all the space ship CGI in HD quality which would cost lots of money. This is the same problem that late DS9 and VOY will have if those shows are ever remastered.
TNG-R gets away with it since all the space ship scenes used models instead of CGI.
The problem is that Warners never treated B5 as an important asset like how Paramount treated Trek.