Back on topic, I have always felt that the designation "major" is somewhat arbitrary, so they should be somehow different. Look at the Women's tour, which changes the majors they play, often simply declaring that Tournament X is their new major......... Its not hard to imagine that "back in the day" those same issues were present for the men's tour, as there was a need to give some highlights to the golf season, which unlike other sports, never crowns a clear winner.
The natural differences to distinguish majors were the national sponorships of the PGA, R and A, and USGA vs. the K Mart Greensboro Open and their ilk. History figures in, and the Masters had the weather, flowers and aura of Bobby Jones.
Architecturally speaking, that meant playing on the finest courses that pros rarely got to see. Remember, in the old days, they played Tour events anywhere someone would put up the money, including on munis in San Antonio and Pheonix. Courses weren't of the uniform quality they are today.
However, it should also be no suprise that the Masters, founded by a player rather than an organization, would be the major historically tilted towards better scoring and aggressive play, no? The next least resistance to scoring has been the PGA, also primarily a players based group.
Presuming you are speaking of the scores at this years Masters in your question, Terry is right - a lot of this is the weather. I didn't watch the Masters yesterday (out doing field work instead) but did hear a few intereviews last night about how the ball wasn't going as far. We don't need no stinking competition ball, we just need to move all majors to Alaska in December!