I know that your post concerns a comparison between Akers and Brown, but I hope no one is dismissing Darrel Henderson too soon.
Though he didn't get very many attempts (or show a lot of production from those that he got), IMO he showed a burst to the LOS that neither Akers or Brown did. It's unclear to me if Henderson is fully 100%, but that last 3rd down run (the pitch play) was better suited for him than Brown.
Long story short...I see Henderson's role in the RB unit. He just needs some time...and health.