Vollmer's been one of my favorites from the start. I think that early on, he (like any rookie) got by on athleticism. He had decent technique early on but wasn't a classic technician like Matt Light for example. There's a lot that goes into playing line at the NFL, and that transcends playing technique alone. If you saw that SoundFX on Belichick, you may remember him getting after Kaczur on "setting for the TE". It may have seemed like he meant tight end, but what he was talking about was the tackle-end stunt. The end crashes down the line and the tackle loops around. It also works in inverse. It takes good awareness to pop and pass the end, then set in your stance to pickup the tackle.
I think that while his technique has gotten to where it needs to be at the pro level, his awareness is really where he has improved. He'll always win a one on one matchup because of the athlete he is. What gave him (relative for the exceptional player he is) the trouble was in picking up zone blitzes, stunts, and overloads. That's only natural for a young player. He's really gotten exceptional at this aspect of his game. He's probably the second best player on that line right now, and is a really unheralded part of that offense.
