[Jeff Rodriguez]

From my observations at regionals, the best alliances are the ones with three good, versatile shooters.
For instance the three robots that won UTC had strong drive trains and could each shoot a few balls.
The benefit of three shooters is in their offensive period. If all three robots can shoot, you can't defend all three. Block two of them and the third one shoots a few. Go block the third one and the one you left starts shooting.
All three of the shooters also had strong, effective drive trains. They weren't easily pushed out of the way, and could be very effective blocking.
The same thing happened at BAE. Three good shooters, with strong drivetrains.

It's not that robot are built to specifically play defense, it's that the robots are versatile. I mean, there is a 40 second period where your alliance has to play defense, so you might as well play it well. That's exactly what these robots did, and did well.