The two situations are nothing alike. We know very little about the Watson case and what little we do know is mostly from one side. You used one of the most publicized murder cases of all time, one where every detail was shared and broadcast on TV live, has been rehashed and relived in countless documentaries and somehow you twisted it into some hypothetical branding situation thats not based in reality what so ever. So yeah, its a terrible analog. I'll stand by that.
With those bust players, people are always going to keep seeing potential, no matter what. Hell, we have a large chunk of people buying into a very obvious bust QB that we traded for based on that potential. So, I do understand how it can be enticing.
This is a different scenario, however. Watson's abilities are completely unquestioned, it just boils down to whether he is going to be possible to sign for a while. If things go poorly, I would suspect we see a Mike Vick type situation, where he is out of the league for a bit and then eventually comes back "rehabilitated."