If you read any true crime books by actual profilers, one early warning sign of serial killers is animal abuse.
exactly
Those same books also tell you that sadists and sociopaths don't get rehabilitated in prison, they get worse. They use their "time off" to develop ever more elaborate fantasies, feed their rage, and work on the "mask" they wear in public. The sophisticated ones gain allies on the outside: the literary community, college leftists, now the NFL and HSUS have become dupes for a sociopath.
Vick a hasn't changed. He won't. He probably can't. For whatever reason, nurture or nature, he grew into a humanoid being without empathy. He lacks the psychological machinery that keeps most of our baser impulses in check. Instead, he revels in those impulses. And he will continue to do so. It's just a matter of time. Manipulate, dominate, control. Cruelty and sadism. Lack of empathy. Lack of remorse. It's easy to see where he goes from here.
Vick fans: While you're forgiving him for what he's done, get in a two-fer and forgive him for what he's going to do next.