Sullivan was a good center on the tail end of his career. He had trouble against more physical fronts - Chicago, NE. He didn't exactly shine in the Super Bowl. then he retired. So I think a younger, more physically dominating center is what we should aim for. Especially when teams are taking away the wide zone running and we are forced to run inside (where Akers can excel).
Cooks was a great addition, but had health issues that kept him off the field. Also, not sure why a guy as talented as he is is traded so many times. I can't remember another player with his stats going through 4 teams in what, like 6 years? Would be nice to have a field stretcher but also a dangerous weapon on jet sweeps and tunnel screens. Josh Reynolds or Robert Woods going in motion and crossing behind the center doesn't scare anyone - a guy with 4.3 speed who can make you miss - just might.