As long as we're quoting famous architects, Dr. Mackenzie said, "In this connection it may be pointed out that rough grass is of little interest as a hazard. ...
Narrow fairways bordered by long grass make bad golfers. They do so by destroying the harmony and continuity of the game, and in causing a stilted and cramped style by destroying all freedom of play."
The key is as George said, having firm enough greens to make players want to hit the fairway so that they have more control over their next shot.
The USGA has always said that missing a fairway should cost 1/2 stroke and over the years, they've had statistics that show that to be true at the US Open. Last week, Tiger, Phil and Vijay hit a combined total of 84 of 168 fairways (50%). They only bogied 13 of the 168 par 4s and 5s. Assuming all those bogies came from the fairways they missed (which I'm sure they weren't), it was only .19 strokes, not the .5 the USGA would like to see at the US Open. I'm not arguing for US Open rough every week, but something more like .3 or .4 might cause them to try to straighten things out. I'm sure that they made more birdies than bogeys from the rough.