Modernism praises simplicity, clearly expressed by slogans like "Less is more" (Mies van der Rohe) – "Doing more with less" (Buckminster Fuller) and "form follows function" (Louis Sullivan). Just take Le Corbusier's definition of architecture: "Architecture is the masterly, correct and magnificent play of volumes brought together in light.". It's simple, isn't it?
Consequently architecture at its best is only providing the stage, the background for more (complex) contents.
John Maeda's fist law of simplicity is: reduce. It's not necessarily beneficial to add features just because we can.
He raises the question:
How simple can you make it? <=> How complex does it have to be?
However, architecture has its own logic of simplicity, maybe more in the sense of aesthetics and formalism than in functionality and technology.
See John Maeda's presentation at the TED conference: