Obviously, but if the a prosecutor had focused the state's case on (1) Trayvon Martin was killed by a single bullet fired by Kel-tec #XX-XXX, (2) said piston was owned by GZ, and (3) said pistol was found in his possession shortly after shooting; and if the prosecutor had not asked any questions that would elicit testimony about GZ's original statements, it would seem like it would have been much harder for GZ to win his case without taking the stand, especially given a judge who seemed inclined to interpret rules of evidence in a manner overtly hostile to the defense. I would think the prosecutor should have been able to establish a substantial lead going into "half-time"; the defense could of course have introduced evidence to support self-defense once it got a chance to present its case, but would have to do so in front of a judge who interpreted rules of evidence in a manner hostile to the defense.
On the latter point, I'm curious why the 7-Eleven video was not from what I understand admissible as evidence? It would have provided the best depiction of TM's physical size on the date of the attack, as well as an exemplar of his voice, and would seem relevant on both counts.
There is NOTHING the prosecution could have done to secure an honest conviction. NOTHING. George Zimmerman was factually innocent. No honest legal strategy can overcome that fact.