But I am also not sure exactly what you want. For example, would it be strange to you if I found ants fascinating? Even though there is no scientific idea at first. Maybe if you look at ants for a while, you'll generate all sorts of ideas (and even in Goedel-Escher-Bach, which I guess is very classic AI, they make an appearance).
So I am not sure that I accept your complaint that you can see no scientifical idea. Actually I am not sure, what is a "scientifical idea"? (Honest question)
Looking at cellular automata I get all sorts of ideas. So I find them fascinating. And why is it not a "scientifical idea" for you to build complex things from simple rules? I don't think it is such an obvious idea.
I am willing to try to answer your question, but first please explain to me what aspect exactly you want to hear about ("scientifical idea").
As for McCarthy, I don't really worry much about what he thinks, especially since LISP is actually from the "classic AI" side of things (I don't mean that as disrespectful - but he is a specialist for LISP and computation, not for complex systems). I think finding the smallest Turing machine was just something to be done for fun - I don't think Wolfram thought much more about it either. So that finding it did not blow McCarthy's mind hardly disqualifies the whole subject in my opinion.
Also, could you link to the No Hidden Variables vs Wolframs suggestion please? It was only a wildly speculative thing, even in NKS, though - not the cornerstone of his world view.