Its designed to stretch the field horizontally. It uses a lot short quick passes in place of a running game. Meaning we should see more rub routes, more WR screens, and passes to the RB on the flat. There should be more drags and slants as well. The WCO puts more emphases on run after the catch and route combinations. There will be a lot of one read pass plays were the other recievers aren't running routes ( they'll never present themselves to the QB as a target ). They'll run clear outs or run to their individual blocking assignments.
Garrett ran a timing and option system. Timing is where the QB isn't throwing to the reciever, he was throwing it to a spot on the field. The WR/ QB options were rwad play. If the defensive player is playing you inside run a quick out. If he's playing you deep run a hook route. In the huddle the QB would say Y-check. That just means lets line-up then the QB will signal to the Y receiver what route he should run, based off his pre-snap read.
But in todays pass happy NFL all offenses incorporate a little of all the other offenses plays and schemes into their mix. So the lines between this offense and that offense don't really exist anymore. Its more about play calling. The Cowboys had all of the WestCoast style plays in their playbook. But they didn't call those plays probably because they didn't even practice them. Because as we all know you call what you practice.