Greens are a huge part of it, I'd agree -- which is why there are only two or three architects working today whose work could be considered "great."But as for underlying abilities, I think that these are the most important:1. Knowledge of golf -- the full variety of shots which can be played -- this is why poor golfers generally don't make the grade.2. The ability to read and understand completely a topographic map, in order to get the best routing possible.3. A sense of proportion and composition in the contouring of greens and placement and shaping of bunkers.4. Imagination.