Scott Parker is better than all of Song, Diaby, Denilson and Wilshere. How bringing in a player better than almost all of our entire midfield starting options would not improve the team is beyond me. Wilshere will probably grow to be the better player, but for now, if we want to win titles, we need better quality control in the centre of the park.
Oh, and part of the reason I like this guy is because I know that I am never going to wake up to find that Wenger has signeed Daniele de Rossi. Parker is rumored to be available, would not be expensive, and he's used to the Premier League. This is a very reasonable transfer target