mr_renoogA possible solution to the problem of leaving too much room for Iniesta (as seen here: http://this11.com/topics/show/5296/mu-4-2-3-1-vs-barca-4-3-3 )
With Park playing on the right, his natural tendency to drift central will be more useful in restricting Iniesta's space (who, conversely, also likes to drift left). That creates an almost-diamond 4 vs 4 in the middle. Abidal will be left free to get forward, but Man Utd can take that risk because the left full back (no matter who plays there) is far less of an attacking threat than Alves.
With Park on the right, this does of course mean that there will be no place for Valencia (who is so one-footed that he would be almost useless on the left). Nani would the most likely player to come in on the left.
The problem with this line-up is that it moves Park away from the left to combat one threat (Iniesta) but instead exposes another (Alves). For this reason I believe that Man Utd should not play 4-2-3-1/4-4-1-1 in the forthcoming CL final.