It’s not the 90’s anymore, most of this discussion is wildly outdated. We won’t be in a base 3-4 OR 4-3 anymore than 30% of the time. You need 5 DB’s on the field the vast majority of the time in the modern NFL or you’re going to get cooked. Having versatile LB’s and S’s is key, something we’ve been SEVERELY lacking for a few years.
Align/call the front 4 whatever you want, but it’s not going to be a traditional 3-4 of the past. 5-1-5, 3-3-5, 4-2-5…they all end up in virtually the same thing after the snap (depending on if/when a blitz happens), it’s really just a matter of giving the offense different looks. And as others have said, what gaps you have your front 4 attacking.