We aren't the only team to be introducing this new style defense. It's not just a different formation it is a radical change in football as we know it.
It means there will be less big lineman on the field. No more will we see the typical 4 big guys on the line. It means if you want to play the interior line on defense in college football there will be less demand for your services. Speed is more important than size. Big means less now. If you're going to start on the interior D you need to be better than players were just a year ago since there are fewer job openings for the big framed DL guys and more jobs for the more agile, speedy mid size guys..
The 3-4 will also cause changes on the other side of the ball too. Offenses will be able to do different things as well as not do things they used to do.
The 3-4 is not a formation change. It is a major change to the game of football as we knew it.