ugly as sin is a definite architectural criticism. if the word beautiful can be applied to contrasting material, textures, compositions as a whole, then ugly can be used to mean the opposite.
Synonyms: animal, appalling, awful, bad-looking, beast, deformed, disfigured, dog, dogface, foul, frightful, grisly, gross, grotesque, grungy, haglike, hard-featured, hideous, homely, horrid, ill-favored, loathsome, misshapen, monstrous, pig, plain, plug, repelling, repugnant, repulsive, revolting, unbeautiful, uncomely, uninviting, unlovely, unprepossessing, unseemly, unsightly
my particualar favourites are uninviting and unappealling. please don't try to give english lessons here alan, we can all be speak good.
this building is not as good as it could be or should be. do you honestly believe there was a decent investment of time, energy, and creative enthusiasm in the creation of this scheme. ignoring the office it came from, or its importance as an urban structure, do you feel it could be better? or is this the pinnacle of architectural expression in your mind?
i also like dogface and haglike.