For me, good attacking movement is the key to scoring goals in the Premier League. With teams so well prepared tactically, the ability of a player to create a yard of space to receive the ball or for team mates move into is crucial to creating goal scoring opportunities.
Quick players are more likely to appear to have good movement as their pace allows them to find space more easily. However, blistering speed is not essential in order for a player to have good movement. Steven Pienaar was a good example of this, whilst no slouch he is not exactly a pace merchant but his movement from the left side of midfield for Everton over the last few seasons has been crucial to the teams success. Until his recent departure it also played a huge part in the effectiveness of Leighton Baines this season. In the two most recent games without Pienaar in front of him Baines has looked a shadow of his former self.
In my opinion improving Everton's attacking movement is David Moyes' biggest challenge for the remainder of the season. This season must now be a write-off but if he can find a system and personel with the movement to hurt teams next year then it may not have all been in vain.