The course had far fewer fairway bunkers when it opened, and the bunker on 10 was originally a greenside bunker, but the green was moved. I agree with Pat about the topography and use of the land being so good as to not need many fairway bunkers.
With some time on my hands, I went to the GD article on how ANGC has changed.
http://www.golfdigest.com/golf-courses/georgia/augusta-changes. I counted the bunkers. Here's what I found:
1934: 29 bunkers in all. 8 fairway bunkers, 2 "in-betweeners" about 40 or so yards short of the green.
2011: 44 bunkers in all. 11 fairway, 1 in-between.
On the face of it, there are now two or three more fairway bunkers. Not sure we can simply compare numbers, though. e.g. #3 used to have one large fairway bunker. Today, compliments of Jack Nicklaus, it has 4 smaller ones, in the same place. (The club wanted to put a lake over there: Jack convinced them to change the mounding/bunker configuration instead.)
Also, looks like some of the fairway bunkers in 1934 didn't come into play, at least for good players. That includes #2, #14, #18, #6 (a small bunker was placed 50 yards off the tee: I guess that counts as a fairway bunker), and maybe #8. Now, I think all the fairway bunkers come into play, except on #10.