I haven't seen anyone directly comment on the prospect that Florida officials may have gone a bit overboard with a 2nd-degree murder charge on Mr. Zimmerman. Here's the definition from the Florida code that will be a great aid to his defense team-italics added.
The unlawful killing of a human being, when perpetrated by any act imminently dangerous to another and evincing a depraved mind regardless of human life, although without any premeditated design to effect the death of any particular individual, is murder in the second degree...
That's going to be hard to prove. The fact that the guy was part of a neighborhood watch program points to something well short of the depraved psychopath the law is envisioning. To do that would require a major character assassination on the part of the prosecution, for it would only take one person our of twelve to say "whoa, isn't that a bit much for this scenario?"
If the prosecution is smart, they'll give the jury the option of a lower, manslaughter-type charge, which seems to better fit the case if self-defense isn't a good fit. However, that might not have been enough to keep the rhetorical lynch mob at bay who would want nothing short of a murder rap to be applied.
The Rodney King case comes to mind, where the first trial had the cops essentially up on attempted murder charges; when the jury was faced with the counter-argument that they were merely beating the crap out of King rather than trying to kill him, they took it and inadvertently set up some of the nastier rioting of my adult lifetime.
If a secondary charge isn't offered as an alternative, we're looking at a similar dynamic in the Treyvon case, where Zimmerman will be overcharged, acquitted and walking. That won't be pretty and will leave the White House of 2013 with the option of doing one of those "violate his civil rights" double-jeopardy end-runs to try him at the federal level as in the King case, assuming that the self-defense charge is weak enough to make a second trial hard to win for the feds.