Ware isn't too small for DE.
He's 250+.
He's the same size as Jason Taylor, John Abraham, and any number of other good DE's around the league. When you combine in the amazing depth we'll have, you'll get to give him some breathers, and he'd be fine playing a lot of snaps there.
Spears is a natural 4-3 DT, he's just like Kevin Williams of the Vikings. Spears doesn't have the low base to play NT but he'd be fine as a 1-gap DT. Ferguson played almost his whole career as the 2-gap DT in a 4-3 so he's fine there, plus Thomas Johnson and Jay Ratliff are both quality DTs, as is Montavious Stanley. These guys didn't come from 3-4 programs in college, they were 4-3 DTs.
Then we can line up Canty on the other side with Hatcher spelling both him and Ware. Canty would be fine as a 4-3 DE. He's not too much of a pass rusher in that scheme but he's certainly not gonna struggle.
At LB, Ayodele goes back to playing WOLB like he did in Jax, I don't see how you can say he doesn't have a position. And, he can spell Ware in certain situations, too, cause he's played 4-3 DE before. Bradie James can stay inside as he's shown he is pretty solid there. Bobby Carpenter is the SOLB, we know he has the agility to do that.
OH -- and I've totally forgotten... we've still got Ellis.
So your defense looks like this:
Ware/Hatcher/Ayodele
Ferguson/Johnson
Spears/Ratliff
Ellis/Canty
Ayodele/Burnett
James/Fowler/Parham/Shanle
Carpenter/Singleton
That defense is just fine.
That is what is so great about the pieces we have acquired. They are fine for either. Ware is the real lynchpin.
You put him on the ground and move everyone over and you've got a 4-3. You stand him back up and slide everyone back and you are running the 3-4.
The defenses aren't "the same," just like that, obviously, the responsibilities are much different, but these guys have the abilities to handle either set of responsibilities.
That being said, I agree, I like the diversity the 3-4 offers us. I think Spears is a BETTER fit as a 3-4 DE than a 4-3 DT. I think Canty is a better fit as a 3-4 DE than a 4-3 DE.
Ware... eh... I think he could be great at either. As could Carpenter.
But I don't think we would have any trouble pulling off a top-5 defense with a move back to the 4-3, either.
I think you will see elements of both this year, with the same players playing in both defenses.