I'm not sure luck is playing a bigger part this year than in year's past. Yes, Roberts and DLee are hitting well out of no where, but that happens. There will be a couple players each year that hit well for no apparent reason, meaning their career projections did not predict their performance. However, out of all the players you listed, many were on drafter's radar screens.
Ensberg, Carpenter, Halladay, Morris, Myers, and Burrell were all thought to have good seasons this year. These were guys that could be drafted lower and had great potential. Also, some of the busts weren't thought of as sure-fire picks either. Schilling, Beltre, Thome (Injury concerns, granted I fell for him), Gagne, Garciaparra, Perez, Benitez, and Boone.
I think the biggest degree of luck this year has come in picking those closers which have actually gotten saves.
...Boston papers now and then suffer a sharp flurry of arithmetic on this score; indeed, for Williams to have distributed all his hits so they did nobody else any good would constitute a feat of placement unparalleled in the annals of selfishness. -Updike