He specifically says that all the characteristics the designer these people are talking about are all the same kinds of characteristics that we started out trying to explain! Intelligence, sentience, forethought, some kind of implementation capability etc.
Now that, for me, is a much better way of putting it. A designer explains nothing because it requires all of the things it supposedly explains in the first place.
I agree that if you rely on the terms 'simple' and 'complex' to communicate something then you have to at some point explain what you mean by the terms. I suspect that it may end up being circular: A complex thing being defined as being many simple things interacting with one another.
And that was my problem. The more I thought about this in terms of simple and complex the more it seemed I was applying circular reasoning.
And for the purposes of this debate - I think that saves us a lot of time. If we are writing a science paper or a philosophical treatise we might want to go deeper.
I think you are right that for the purposes of this debate defining simple and complex is unnecessary. Instead we should just think of this in terms of what it is we are trying to explain in the first place. And recognise that invoking the same things we are trying to explain as the explanation is rather pointless.
Well it makes more sense to me like that anyway.