Unique Art =/= Good Art
Akagi had unique art, but I found it visually abrasive and ugly. It's not cohesive.
I know, with artfags, it's a matter of opinion, and I have nothing against Akagi-lovers, but I just find rich, soft, lush settings and colors more visually stimulating than stark, base, angular and stolid stick-framing.
Kanon and Clannad just had quality art in my opinion. Yes, arguably generic with nothing to set it apart from other animes in the genre, but compare the color-scheme and illusion of depth to other current animes like H20 or Spice and Wolf, and you'll she a big, big contrast.