It’s a great D for FCS where you have slower lineman and you can use tween speed off the edge and quick fills to a defeat less mobile line. It doesn’t work with fast big-men that neutralize the speed over size advantage. 215 pound linebacker/db has no chance against FBS lineman with quick feet and good hands. They can’t get off blocks, can’t rush and are pushed down field.. What you get is a weaker LB and when is coverage step slower DB that gets beat. It was a bad idea. They were always going to get physically beat.A couple of counterpoints to the 3-3-5 criticism:
Big athletic humans were not easy to find. That staff could barely fill out the roster on 0-line, D-line or backer. They did recruit lots of smaller guys that potentially could play the schema.
The conference was full of gun slinging QBs at that time. That alignment could have created problems for them.
Obviously, it didn't work, but it did not seem to be a random idea without any basis to me.