That this attempt was made at all was because Rover was owned by BMW at the time, and the Germans hoped a new Rover would make their investment pay off. The Wikipedia entry for the Rover 75 is here. According to the Wikipedia link, both BMW and Rover management thought that conservative, dignified styling would be appropriate for the new model.
Also according to the link, the design was fairly well received, but sales were not as strong as hoped, behaps due to concerns about the company, which BMW sold in 2000.
I visited England several times when Rover 75s were in production and could seen fairly often on streets and motorways. I thought the styling was blandly pleasing and Rover-like: just what a conservative mid-line British car should be. My biggest quibble is the zig-zag cut line in the front fender area for the front end impact cap. An effort should have been made to integrate it in some way with the upper character line on the fender.