I was a SPED teacher -- and definitely struggled with the SPED-specific aspects of my job (the IEPs and legal compliance, e.g.) more than the other aspects of teaching. And that, I think, was due in large part to the fact that TFA had tons of resources to help me improve my pedagogy, but very little to say about what it meant to be a good advocate for the legal rights of my students. Within my district (Philadelphia), too, the resources for being a good SPEDucator were few and far between because the district's incentives were misaligned with regards to their students with special needs. (Any commitment on the part of an IEP to provide services meant additional costs for the district, so we were explicitly cautioned against adding add'l services for speech, OT, PT, etc. on our own).
Re: turnover, during my second year in Philadelphia, the district also went through huge budget cuts and ended up laying off ~1,500 teachers--many of whom were first- and second-year teachers. The consequence of which was movement either to charters or out of the classroom... This isn't to say that TFA isn't responsible for encouraging (or excusing) teachers who leave after two years, but it does remind us that there are broader problems with teacher retention.
Also, EML -- thanks for (re)starting this convo among us TFA'ers. I'm sad to say that I'm one of the teachers who left after two years, and frequently wonder whether I should have stayed in a classroom (though likely not in Philadelphia, given the layoffs).