There was Christine Grace, who was arrested, charged with second degree murder, and then convicted of manslaughter after stabbing her abusive boyfriend as he was beating her senseless in her kitchen, inviting friends to come join him. This was in '89.
There's Marissa Alexander that's currently being prosecuted by Angela Corey when all signs point to her having had immunity under the SYG law. She's been in jail since the alleged crime took place (and she never even injured anyone).
You also have this woman:
http://www.wctv.tv/home/headlines/80750267.html
Who was arrested, charged with second degree murder, and held in jail on a $50,000 bond... Only for a judge to have the charges dropped because he ruled she acted in self defense.
Here's a more recent case that occurred while SYG was even in effect. The man was incarcerated for two years (before he was even tried) before he was finally able to reach an appellate court, who found that he was immune per the law.
http://opinions.1dca.org/written/opinions2009/08-19-2009/09-2501.pdf
It's odd how you claim that the law grants immunity unfairly, but it seems that victims are still capable of getting wrung through the system with the new law in place. As I stated before, if the police are corrupt... they're corrupt. No amount of legislation will change that. It's ultimately their decision to arrest someone or not, or to carry out an investigation. As you can see, that option still clearly exists and is exercised.