The upsidesUpsides of writing an expose include:
You would get the emotional satisfaction of ranting about your former boss.
Someone who is considering working for the guy might read it. Or not. Probably not. (It's a big Internet)
The downsidesDownsides include:
As mentioned, itIt is improbable that it will have the impact you want. Will anyone considering working for him will actually read it (it's a big internet)? You would have to make it highly specific (naming names) in order for anyone to connect the dots and avoid this guy, and even then, who knows?
It makes you look bad and could get you blackballed. To be perfectly honest: if I was was considering hiring you, and I googled your name and found your "expose" (rant) about your former boss online, there is no way inno way in the world that I would hire you. No way. When making hiring decisions, you have to form a picture of a person very quickly based on very limited information. And your one-sided "expose" (rant) would be a big red flag. I would worry that you are a complainer with questionable judgement (who has demonstrated a willingness to write "exposes" (rants) about former bosses online. Would I be next?).
It will possibly get you sued for libel / defamation, and damages. You mentioned that the guy is sue happy. Even if he is wrong and you are right, and even if you win in the end, he can ruin your year with an expensive lawsuit.
Conclusion
In my opinion, the possible benefits do not outweigh the probable consequences. Yes the guy sounds awful. Write your expose inFlood your (offline) diary with rants about your bad experience, and tell friends about your lousy former boss over some dinner and wine. But I would not recommend against writing any exposes or open letterletters or any warnings online. The Internet has a long memory, and the consequences can be very real.