Give PBS time. Not everything gets released on Blu Ray. So far the only shows on our man Ken's resume to go blu ray are National Parks and 10th Inning (coming out next week). They actually were gonna reissue an all blu copy of all of Baseball, but changed their minds. Give them time, when it happens, it happens.
The only difference is that strange artifacts will appear in the footage. The series was originally intended to be displayed in NTSC; DVD remastering is a stretch for the source material... Blu-Ray would be a farce. Higher definition isn't always a blessing.
Leave aside Blu-Ray possibilities........why can't you buy this set new on DVD here? I mean of all the titles to be "out of print", so to speak. Especially given that next month the Blu's for Gettysburg and Gods and Generals are coming out (with longer cuts no less), which will make Civil War buffs and such look to their shelves for Ken Burns......and if it's not there, it can't be bought here. Weird.
That said, J. Allen makes a great point about the source material, I hadn't thought of that before.
So far only 2 items on Kenny's resume have come out on blu and on the same day as the new release, 10th Inning and National Parks. From what I heard here on Amazon, the blu ray copy of 10th Inning was flawed and God knows how National Parks came out on it (the standard version is great). They were supposed to reissue the complete set of Baseball in blu originally, but just before the premiere of 10th on TV, PBS yanked it. If the stories about the blu copy of 10th are true, then it is good they did. My entire library is standard definition including all of Ken Burns resume which I include, his brother Ric's New York and Stephen Ives' The West in and they all look great as they are. Why fix what isn't broken?
Considering that The Civil War was originally shot on film (IMDB lists is as on 35mm, Wikipedia states 16mm, which seems correct), and it has been shown theatrically, there is probably no technical reason it couldn't be remastered in HD/Blu-Ray. Remember, they took The World At War up to HD and it was made from 1969-73, long before HD was even a remote possibility. Not all aspects of it look good, especially the videotaped interviews, but what was originally on film is considerably improved. I'm guessing The Civil War would look pretty good on Blu-Ray, but considering the length of the film, it would be a massive project that I'm not sure PBS/Ken Burns wants to take the time/effort/money to do when there are other new projects still on his list.
The original 16mm film copy has been digitally cleaned, color corrected, stabilized and enhanced. Not sure that they plan to do a blu-ray version, but the new DVD release should show real improvement in picture quality. The soundtrack which was monaural, has now been remastered into Stereo, and into 5.1 Dolby Digital with sound effect and musical enhancement. The dowdy looking DVD set that is on many folks shelves can now be replaced with a product that will look and sound much much better.