Yeah, I really don't understand the infatuation with going to a 3-4 either. These things are always cyclical. If a third of the league is playing the 3-4, it makes it that much tougher to land the personnel, like, for example, a stud nose.
I'm not for or against whatever defense a new coach wants to install, I'm just saying moving to a 3-4 doesn't guarantee a better defense.