In response to the people who think Andy is not one-dimensional, by 1-dimensional we don't mean Andy can't slice, or serve and volley, or play defense, or change it occasionally. By one-dimensional we mean even if he changes it up every now and then -- which all players do -- he only has one effective game plan. I'm talking about actually changing strategy for a whole set or two, and not just what he might do from point to point.
Ljubicic basically said in an interview that Roddick doesn't change his game enough, that everytime you play him, you learn more, and that if you're reading his game, especially his serve, you can eventually beat him.
The thing is, IMO, everybody on the ATP tour at this point probably knows how to beat Roddick, but very few people have the skills to pull it off. His one-dimensional game is still good enough to beat 95% of the top 100 any day of the week on hard courts.