I think that defensive formulas are tough to come up with in regards to this years FRC game. Some of factors that influence this are size limitations related to specific locations on the field, obstacles of the course(towers), etc.
I am an ex basketbal coach with 22 years of coaching experience (high school and college) as well as coaching several other sports for many years. As a basketball coach, I am of the opinion that making a player get to their sweet spot (so to speak) makes a player work harder to be comfortable. If they are uncomfortable, then you can begin to effect them.
I do not think that blocked shots are the key to great defense unless you are talking specifically about full court shooters. Most full court shooters want to align to the goal and line up for the shot. If you get in the way of the shot, they move to the pyramid to shoot thus making them a cycle runner. Very few are willing to stay true to the long range shot by just moving to another location on the field.
For pyramid shooter/cycle runners, make them work hard to get up and down the court. Middle cuts, side cuts and under the tower cuts are all moves that a defensive bot should be able to do. FRC 2789 did an excellent job of all of these at the Lone Star and Alamo Regionals. In Semi Final 2 match of Alamo, they occupied two other robots for 100+ seconds of the total 240 seconds for those two robots. That time equates to stealing cycles from their strategy. Martin did an excellent job of driving as well as taking coaching to change strategy throughout the matches. Watch the middle of the field in this video for reference:
http://www.youtube.com/watch?v=xM1WIp2qe-I Notice that on several occasions, the opposing robots have to take a different path to get to the feeding station thus stealing time off the clock.
Defense of a cycle runner is not just trying to push them around but rather making some contact, not afraid to be physical, and cutting off paths.
Patterns are easy to predict if you watch enough matches. Coaches of sports teams watch endless hours of video and use all kinds of ways to try and predict the patterns of not only plays but even more importantly specific players.