Alexa.com can give you some information, but it is not very accurate. It will just give you an idea of what the traffic may have been. Try it with some of your sites where you can check the traffic and you will see how much you can trust it.
It's better to look at the current backlinks to the domain for this kind of information, and even then since the old site is gone, any traffic it is getting may go away because the old site is gone.
Archive.org can let you see what the old site looked like and you can see if it was a good site or not. For the most part, the history will not affect what happens to the domain once it expires, is dropped, and then registered again. This is my opinoin anyway.