The complexity of scheme is bull$hit, and quite frankly, unnecessary. The best defenses are ones that play fast. The only way you can play fast is to have guys understand what they are doing.
If that means checking your ego at the door, and dumbing down the playbook, so be it. Buddy Ryan did that back in the 80's with the Bears when he had his leaders on D tell him guys didn't know what he was talking about.
That move alone elevated the Bears D to legendary.
Complexity is fine if you have the team that can digest it and executes it. If you don't have that, then you have the Domfense.