The defensive system you use as a foundation isn't nearly as important as the players deploying it. I have always felt that there are a lot of inovations that can be used to disrupt the flow and blocking paterns of the offences we see. I like a defense that is unpredictable and can't be read by QBs. Why not shift in and out of 42s, 33s, 24s, 43s, 52s, 44s, 25s, 23s, and what ever else makes them scratch their heads. As long as you are covering the running lanes, containing the edge, preshuring the passer, and covering recievers, then disrupt them, stop them or turn them over.
Championships are made of defense. Defense, at iys best, disrupts, confuses, and deflates an offence.