Sweat is the only one mentioned that was a difference maker last year. Curl and Fuller had relatively bad seasons. That being said, I'd take Luvu over all 3. I also think having Wagner back there is a significant boon, even at his advanced age.
You want to call it a push for the start of last year and the start of this year, sure. I am willing to put money on this defense finishing in the top 20 defense and not dead last like the bums we fielded last year.