My first reaction is that this is sad, Pulpit and Pen helped me out of the New Apostolic Reformation movement recently. The articles on that website are very powerful, at least in the fight against Charismatic chaos.
Looking at it:
Why I've Left the Convention, J.D. Hall, February 28, 2013
I don't have enough information to agree or disagree on many areas, but I do understand his gist, which I have struggled with too. I came to the conclusion that there are no perfect churches in America, yet there are a number of genuine believers at some of those churches. I mean my new SBC church seems on target in most areas, but lacking in some. I see those as opportunities to grow where I can, and one day talk to the leadership about areas that worry me when I am more mature.
Then again, in this man's case it sounds like he was hated for his acceptance of the doctrines of grace, which I personally don't believe in. But I would hate to sanction others for believing in them, as I cannot refute them entirely.
I also have to say that he comes off as holier than though a bit with his intro. That said, it sounds like he is leaving because of missions disagreements with the SBC, which is the whole point of being in the Convention, so yeah, he wouldn't stick around.
Though I have a similar concern in the SBC, that I can articulate now by reading that article. That concern is the fact many people don't understand how to be saved, through faith in Jesus Christ, and confirm that salvation, through obedience. That's a matter for another thread, though.