The falcons make the playoffs every year with a 4-3 defense. The Saints won a super bowl with a 4-3 defense. The bears are top 10 every year and they play a 4-3. I guess those teams are "stale". The Rams and Seahawks have much improved defenses and they play a 4-3 and the Lions are ranked 9th playing a 4-3.Then you have the cards who are a much improved 3-4 defense as well as the success of the Texans and the 49ers but the Browns were bad for years playing a 3-4. Whatever scheme you use you have to coach it well and draft the right players for it. I personally prefer the 4-3 and drafting a great defensive line.