While this is a columnist piece and not beat writer discussion, these are all issues that Cecil Lammey and Sigmund Bloom and Sean Baca had concerns with when the switch was made and have continued to note all offseason long -- Williams struggling to grasp the MLB position, concerns that he doesn't have the mean streak many MLB have, etc. Some of those issues can be coached and learned, the instinctual things obviously cannot.
Sig and Cecil also strongly feel that Williams will not be moved from the MLB position -- it's his. They're closer to the situation, but I completely agree. If they haven't moved Williams by now, they're pretty unlikely to given the injuries on the strong side.
There are a lot of factors here, as Keg noted, DJ in a new spot, the entire defensive line turned over, new scheme, etc. DJ may take a bit to get going, but he's extremely unlikely to move and the tackles will be there in this scheme. Temper your expectations a bit, but Williams will be a LB2 at worst.