LoGH is old enough that the majority of it was cell animation. That masters can be rescanned up to just about any resolution. So there shouldn’t be any need for upscaling, unless the Japanese production committee really cheapened out. More than likely, any anomalies or flaws in the bluray were the result of poor encoding or production practices.
It’s also possible, and quite likely, that they overcompensated for some flaws and grain the original masters and went to far cleaning them. This is quite common in commercial bluray releases of older shows and movies.
Q. I have asked this question before (and never gotten an answer) but will Legend of the Galactic Heroes be released season by season or all at the time?
A. We cannot release any home video details about LOGH prematurely to any official announcements.
Q. What is the status on the Legend of the Galactic Heroes release? The Ask Sentai section hasn’t mentioned the title since 2015 and it’s making me worried.
A. Still being carefully, meticulously worked on. They talk SO MUCH. And it all had to be translated and localized. We’re not going to forget a large, high profile project like that, but we also can’t announce a date and then keep changing it, ya know?