what seemed to me to be a genuinely stupid, clumsy bit of writing that gave the appearance of being self-contradictory
Dear sjmaxq, it is a given that the best advertising copy is copy which people notice and which people remember. If the copy generates light-hearted discussion [eg. is it good grammar, bad grammar?], that is a huge bonus.
Measured by these standards, the sample you brought before us, "one small but immense improvement", is neither "stupid" nor "clumsy" but, instead, clever, provocative and wildly successful.
Forever after, all of us will remember the phrase "small but immense improvement" and we will simultaneously connect it with office furniture. You have paid the author of the ad the highest compliment available. Whether or not you like the ad yourself is quite beside the point.
The only thing you didn't do is name the manufacturer of the office suite.
You have certainly piqued my curiosity. Where can I buy this furniture? [I have a small room where I am dying to make an immense statement.]
