Perhaps MPI Home Video, the company responsible for releasing the official VHS cassettes in the late 1990s will acquire the rights and give the show a proper DVD release in the correct aspect ratio with no parts of the picture missing, as well as color correcting the night scenes.

Yes, there is an artificially created wide screen effect and each version (as far as I know) has the day for night issue. It's even on the version listed on Hulu that occasionally airs on Chiller. I only have the first DVD release so I can't say for sure about the re-issues though.
The day for night issue was not on the VHS tape versions.

Which DVD release are you referring to, because apparently there are several; the original 2005 version (cover featuring Barnabas' face in the moon), as well as a 2009 re-release with Victoria and Barnabas on the cover. There's also another version that only has Barnabas' frightening face on the cover.
To make matters more complicated, the 2005 edition is listed as 1.78 aspect ratio, and the 2009 lists a 2.35 AR. Meanwhile, this show was most likely shot in 1.33 (fullscreen), which means there is an artificially created widescreen with the top and bottom cropped.

Remastering shouldn't ruin day for night scenes.

because the material was remastered for widescreen Hi-Def when it was prepared for DVD and no such effort was made for the VHS.
http://darkshadows-resurrected.com/
http://thebluewhalepub.com