Unfortunately, Tannehill's too entwined with the quagmire that is Philbin/Philbin's friend/Philbin's friend's son-in-law to buck the trend and stand up and be a vocal leader, especially ins his second year. Plus, I just don't see him as that kind of guy.
I've been acquainted with Cam Wake since he was Derek Wake playing at Penn State. He's a guy that could carry a lot of cache coming back from a major knee injury, then going to the Canadian League and making himself a Pro Bowler. From what I know of him, he's a guy that could fill the vocal leader role quite well. But, as is mentioned above, when you see guys who filled that role get jettisoned, it's probably enough to make anyone think twice about speaking up.