Though my body of work is only 22 holes , I'll opine.
Certainly the client tells you their desires and the architect reacts to this with both a reality appraisal and their own personal beliefs in what they like and want to design. This answer will vary with each site and with the specific goal of the project . Obviously Streamsong was a different job than Hamilton Trails , a nice little 9 hole muni in our backyard here in SJ.
As architects grow in stature and demand , they can exert more influence on what they choose to build. Obviously Coore & Crenshaw and Nicklaus don't need to listen as much to the client ,though they may very well do so. They can pick and choose jobs to a great extent. Their reputation, body of work and talent has given them this privilege.
From a strict design standpoint ,it seems the best designs allow for lots of players to enjoy , yet can be tweaked for tournaments for the expert players. This typically means fairly wide playing corridors and some variation in tee lengths , say from 5500 to 6700 yards. Greens tend to separate the really good course from the run of the mill. So, time and effort in making them the best your budget allows is critical to excellent design.
When building a course like Sand Hills , Bayonne or Pacific Dunes however, where the site gives you so much inspiration , the great architects tend to let their creative sides manifest to a greater extent and typically take a few more chances. that's why courses like this are such a treat to visit!