Jake, Wilson WAS a great run defender when he was allowed to hit high and knock people out. He was barely effective as a run defender when he was forced to lower his target area to conform with the concussion issued. He bounced off ball carriers far too often without taking them down, because he was a thumper, not a wrap up tackler.
Our whole defense was poor at wrap up tackling, which caused us to finish so low in run defense. We will have lost little at the strong safety position, as the new management team brings in new players, (and there WILL be new ones to come yet). Most of all, the contracts of the safeties were necessary to force their removal from the roster so that we had money to make numerous replacements, (not just safeties).
ALL the players that we have brought in on defense ARE better tacklers than we had on the roster, and that includes Campbell, Dockett, and Lenon. (Haven't you ever asked yourself just how many sacks Campbell COULD have had, if he simply would wrap up his target instead of just hitting him). All these new guys are form, (wrap up), tacklers who take the ball carrier to the ground. That is why we have improved the run defense, (that, plus teaching new fundamental techniques to our old remaining roster).
I don't think you have given the new free agent acquisitions enough credit for the types of players they are. They are all young with much upside, (with the exception of Bell), and Bell will be given more help by way of new drafted players, and possibly another free agent signing. These guys are fundamentally sound already, and are self starters and gym rats who love to hang around and learn from others. This staff will bring out the best in them.