WCO relies on multiple formations and multiple pass routes, depending on the defensive set determined at the LOS by the WR and QB. If you recall Klatt as QB, he sometimes would heave the ball to a TE or WR who would turn the opposite direction from where the ball was being thrown. The QB and WR have to make the same read, and that takes tons of reps. Since CFB has practice limitations of 20 hours per week IIRC, it is very difficult to get the WCO running well.
Here is a WCO playbook model: It is a very complicated offense, http://www.playbookexchange.net/playbooks/Offense/01130301-WestCoast.pdf
There is a lot more to it, but that is it in a nutshell.