AJ, the fundamental problem for Zimmerman is that, on tape, he chased someone who was running away from him - having done that, to regain his right to self-defence against that person is nearly impossible. Literally, he'd have to have done something as drastic as getting down on his knees and pleading with his hands in the air. That's why it is a bad idea to chase when armed - if it turns out you chased the wrong guy, you are going to be in serious trouble. It's so bad for his case that a defence which is sufficient to overcome the chasing, and at the same time beleivable, just isn't realistic.
The key here is the chasing - you chase someone who wasn't doing anything wrong in the first place, and you aren't going to be able to claim self defence if you end up shooting the guy. Whether trayvon pounded him after the chase or even hid in the bushes and sprang out will only matter at sentencing time, it's not going to work for a defence.
The more this case goes on, the more it reminds me of the Scott Peterson case. The media invented this impression that it was a close call, but in reality, the conviction was pretty much guaranteed from the day the body washed up. There were tons of pundits carrying on about this or that legal matter, but it was 99 percent fluff. No technicality or bs about satanic cults was ever going to work.
And today there's another similarity - zimmermans attorneys have withdrawn from the case. Zimmerman, like peterson, is going to the media and apparently buying in to the stories told by throngs of online supporters (Peterson had a big fan club too.).
This is a sure path to conviction folks. Shouldn't be a surprise, but some will make it out to be when it happens.