I think Searcy can get it done, myself. I also disagree with you regarding Aaron Williams being better in man coverage (opposed to zone play). He doesn't have a good enough burst of speed to catch a receiver if they beat his jam at the line. If he can develop an understanding of where/how to play within a zone, i.e. anticipation of where the receivers passing through his zone are planning on going it will help negate his lack of speed and acceleration, and also hide his lack of fluidity in the hips.
However, it is a moot point, as man coverage will likely be the order of business for the CBs in the new defensive system. I think having Gilmore constantly covering the opponents #1 receiver will help Aaron in the future, a trend I believe will continue into Pettine's reign. His first few years he was at times matched up against #1s, which is when he often looked so bad. He can match up better with smaller, slower #2 type receivers, especially in the "possession receiver" types I believe.
"I don't like the Dolphins, I don't like the Jets, I don't like the m- f- Patriots! I don't like the Browns 'cuz they start with a B! Let's go Bills Ba-Ba-Ba-Ba Bills, Let's go Bills!" -If you hear this being cheered at Bills games... I am likely the one you are hearing!
No one circles the wagons like the Buffalo Bills.