I believe he was scheduled to appear in Phase II's "In Thy Image" and was dropped. There are definitely set plans for his office. I think the production wanted to get a big name actor to play him. Perhaps this fell through, and hence he was omitted?
Joe Jennings actually BUILT his office for p2, and the set elements were recycled by Harold Michaelson into the cargo deck in TMP.
There have been tiny flutters that Toshiro Mifune was going to play Nogura, but I think that is just some confusion from the fact Phil Kaufman wanted Mifune to play a klingon Captain for the unmade PLANET OF THE TITANS feature project that was cancelled by Paramount right before they put p2 into development.