So while the course remains shorter than the average Open venue, the World Golf Hall of Fame member said that Merion will be "an interesting test" for the world's best players next June.
"They changed the golf course to fit modern equipment, and it didn't need to change prior to that," Nicklaus said in an e-mail response to questions from The Inquirer. "It was always a bit of a shortish U.S. Open test but a good U.S. Open test. With today's golf equipment and golf ball, the golf course needed to evolve to remain an Open test.
"Merion is now certainly long enough, but it's long in a different way. It's long in the fact that there are some very, very long par 4s, and also some very, very short par 4s, but not many in the middle. It's a little different. There will probably be a lot of birdie holes at Merion and a lot of bogey holes at Merion. It should be an interesting golf course."
Nicklaus, the winner of four U.S. Opens, said he can see a winning score of something less than 10-under-par, which would be close to the 7-under posted by David Graham in his 1981 victory.
The course, which played at 6,544 yards in the most recent Open there in 1981, was stretched out to 6,846 yards for the 2005 U.S. Amateur and probably will come in at more than 6,900 for 2013.
Nicklaus wonders whether players will give a go at trying to drive the green on Merion's shorter par 4s, such as the first hole, which plays at 350 yards all the way back but might be moved up to tempt the contestants to try the riskier shot.
"Before, you wouldn't even think about driving the first hole," he said. "But today's players with today's equipment, you can now think about driving it. A lot of fellows will probably take a run at the first hole, although I don't know whether that's the prudent thing to do."
Nicklaus said his visit in May was the first time he had been at Merion since 1981. Of that year's Open, he said: "I don't remember how I played. I don't think I played that great, but I wasn't too far off."
Nicklaus stood in third place after 36 holes, 2 strokes off the lead. But he went 71-72 on the weekend and wound up at even-par 280, 7 strokes behind Graham, the champion.
Much speculation surrounds the setup for the 2013 Open, but Nicklaus said he likes what he has seen of Davis' work, particularly at last month's Open at the Olympic Club in San Francisco.
"I think he's done a good job," he said. "I have never played one of Mike's courses. I thought Olympic was set up pretty well."
While the concern is that today's younger and stronger players, using cutting-edge equipment to propel the golf ball tremendous distances, will overpower Merion, Nicklaus doesn't think so.
"With what I saw when I was there [in May], I think Merion will do just fine," he said.
Contact Joe Juliano at 215-854-4494 or email@example.com, or follow on Twitter @joejulesinq. Read his blog, "Golf Inq," at www.philly.com/sports/golfinq