I hear you and I can't dispute what you are saying since I have only focused on Ballard in 2 games (Wisconsin and Missouri). He didn't seem soft in either of those games. In fact I was impressed with his discipline...gap discipline when he was inside, containment when he was outside, collapsed the pocket without over-pursuing and getting taken out of the play.
We all seem to get riled up about players that dive into the backfield with their hair on fire...but that doesn't seem to fit what Belichick is looking for. Instead of 2 sacks and 18 times getting escorted neatly around the pocket...Belichick seems to want 20 rushes where you influence the play every time. If he can't eat up blocks and hold the line against the run, all that is moot. He looked capable to me in the limited time I saw him.
Cunningham and Deaderick were unheralded picks but they seemed to fit this profile. I'm thinking Ballard does as well. A 6'4", 300 lb guy that can run a sub 4.9 40 has a significant amount of physical upside. If you can get that guy with a 2nd round pick, seems like a good investment to me.