I like Alan Kay's saying that "a point of view is worth 80 IQ points" (http://billkerr2.blogspot.com/2006/12/point-of-view-is-worth...).

In the end I don't think that it's either mostly about intelligence or mostly about the system but a balance, where good system will multiply the effectiveness of intelligent people.

We can find examples of few intelligent people in the right place creating astonishing breakthroughs (see Xerox Parc). I would think that if they were not above-average smart, they wouldn't have done what they did, so we shouldn't under-rate being smart.

On the other hand there are also examples of undoubtedly smart people creating over-complex, broken designs (e.g. SOAP) so pure intelligence is not all there is.