I don't know much about who are becoming new JW's, because I'm not one myself. I do know that someone was attracting me into the WTS, and I consider myself a normal guy. I also met some people who either became or were close to become JW's, and they also seemed normal. And I met some people who left the organization and they seemed normal, too.
I do believe that the point here is that the organization is so concerned about bringing new converts in that the publishers will not spend their time converting, say, someone who is hard-working, honest and normal but is not that willing to accept a magazine, for example, but they will indeed spend time trying to convert someone who is responsive to their ideas but is a little crazy. And, since the organization gives that much importance to WORKS, then it would gladly accept someone who, say, has a very questionable past, under the assumption that once he does what a good witness is expected to do his inner person has changed too. I understand that becoming a witness does force people to change their personality and behavior, but I wonder if this would go as far as, say, changing an abusive person into a less abusive one. From the posts on this site, that does not seem to be the case.
Steven Hassan says that cults tend to recruit the people who are smart and would become an asset to the organization. I'm not sure if this is the case with most converts. They might be an asset if you look at them as "another member", but I wonder if they really bring something new and innovative to the organization, other than their hands and willingness to knock on doors.
A similar point was made by an evangelical I saw on TV. He claimed that many evangelicals had been rescued from drugs, bad lives and the like, and so many of them had a less than pure background, which was something they had to recognize. The evangelical's purpose, of course, was to say that they all had been changed, and that no one should feel above others because one day they had been below others, too.
I wonder if JW's are really concerned about who they bring in, in terms of their original morality or their real change. Yesterday three ladies came to knock on my door, all middle aged women who had converted from another religion. They felt they had become more spiritual. That's OK, they are not nuts, but, suppose someone brings in a former criminal in. Would you want your daughter to marry him, because he's now a brother?
I guess JW's would be more selective about who they bring in if they were not that obsessed with numbers. A mistake leads to yet another, and another...