I don't understand how you can conflate a serious plot-driven political drama like Maschera with a silly cuteness-driven fluff show like Stardust Witch Meruru!
Cardcaptor Sakura 5:
This show aired between 1998-2000. So it was made during the early digital era, originally with a 4:3 aspect which is properly windowboxed on my HDTV. However, close inspection of the picture makes it look like it wasn't made for SD digital, as it's pretty damn decent looking and seems to be cleaner than an upconvert of an SD digital program. It looks like it was animated the old-fashioned way, on cels, which were restored, transferred to a new master, and prepared especially for the HD release of this show.
Also somebody went through the trouble of remastering the soundtrack and creating a 5.1 channel surround mix. They did this for all 70 episodes. The scope of such an undertaking is pretty impressive, to say the least, and yes, they took all the original sound elements and placed them discretely in each channel, dialogue is placed entirely in the center channel, and when things fly around or Sakura does her magic, the sound is placed in the surround channels. The amount of effort that went into the remastering of this show is breathtaking, quite frankly. It is Madhouse though, I shouldn't be surprised.