DS2 is ugly as hell, because it often contains rooms that are just in shape of cube with one texture for walls and second one for floor and maybe 2-3 decorative items. Even when you have arches in doorways or stuff like that they’re often just standalone model that covers the sharp edges of simple rooms made from a few faces.
Or look at floor texture in Things Betwixt - it’s one small rock texture with grass patch that is obviously repeated.
Or take church before Freya fight, the one with spiders haning from the roof. It’s empty. Again, big empty cube with a few small props thrown in. That’s the stuff you can make in Blender after a few hours with a good teacher showing you what to do.
Compare it to a smaller church in Undead Parish in DS1 - you have two entrances, an altar with a sculpture, benches, columns, archways, stairs, elevator to Firelink Shrine etc. Or church with Ariamis painting - it have Gwynevre statue (amazing chest ahead), some large columns, broken giant chandelier, the painting itself and some higher places you can visit there.
Hell, even a single room in Anor Londo, despite also beign just an empty cube is more detailed (paintings, tables, beds, carpets, candles, fireplaces, windows and other stuff I don’t remember) than most of crucial locations in DS2.