Both Mauna Kea and Cog Hill No. 4 are only "new" to the list because they were booted off in 2008 because they were closed for renovations. They were regulars on the GM lists before then -- though if I recall correctly not ranked quite as highly as they are now.
I may be beating a dead horse, but the most astonishing thing to me about the list is the omission of the Ross course at French Lick. I think it belongs in the top 10. Does anyone who has played it agree that it does not belong in the Top 100 at all?
More generally, other than a few famous names, there are hardly any classic courses on the list at all. There are four courses from before 1950 in the top 15 (Pebble Beach, Bethpage, Pinehurst No. 2, and Pasa) and another two from before 1980 (Spyglass and Harbour Town). After that, there are a total of eight more pre-1950 courses in the next 85 (Cascades, Sea Island, Taconic, Dunes, Pine Needles, Greenbrier, Linville, and Broadmoor) and a total of seven more pre-1980 (Golden Horseshoe, Innisbrook, and Doral, plus four that have been substantially renovated in the past two years, Cog Hill, Mauna Kea, Torrey Pines, and Bay Hill). Over 80% of the courses ranked from 16 through 100 were built in the last 30 years.