your aproach to "anime" is such a bad generalization for this kind of thread
the only way to actually make an argument about anime graphic quality would be comparing specific works from a single studio
say compare the graphic quality from Gainax in the 90's in EVA or Kare Kano to Gurren Lagan, I don't think there was any kind of detriment there, the animation is more fluid, less standing scenes where they only move their lips and such, vibran colors and not overusing digital light sources
Say Gonzo, compare Nadesico to Gankotsuo, I think it's pretty obvious they pushed it a good deal ahead and attempted another style using more modern techniques avaiable 10 years later.
So which works from which studio can you name that have lowered their image quality, from moving to digital media or such? or is your rant "design only" focused, because I'll admit I don't dig the noseless chars in oban star racers but that's not a fault of the anime, the char design from the manga was like that....