First off, Wolfram's attempt to classify automata into four categories is flawed: it isn't obvious that every cellular automata falls into one of those categories and not all the categories are even rigorously defined. Also the claim that not many other "definite class-4" automata were found is unhelpful. The ways that things can turn out to be Turing complete are often surprising and non-obvious (cf for example the word problem or Hilbert's 10th problem.) So the claim that an automaton rule isn't obviously Turing complete is extremely weak evidence that it isn't.
The fact that 1D cellular automata are weak is both unsurprising and not good evidence for anything. From a Solomonoff perspective, adding in extra dimensions is pretty cheap (Tangent: one issue that I don't fully understand is why we shouldn't be deeply surprised by how few dimensions our universe seems to have. One of the strongest arguments for string theory that I'm aware of is that it answers this by saying that there really are more dimensions. However, string theory doesn't really do a satisfactory job in that regard because the behavior of the individual dimensions is likely to vary, while the Occamian approach predicts that dimensions that are all treated the same way should be cheap.) But there are all the 2D automata and no one has even done almost any investigation of low dimensionsal automata for higher than 2. 3 and 4 dimensions would be the obvious ones where interesting things might happen. And there's also been very little work at automata that uses a basic tiling form other than squares (e.g. equilateral triangles, or hexagons, or pairs of octagons and squares with possibly different rules for the two types.)
Incidentally, I suspect that most of the so-called "chaotic" cellular automata are Turing complete but simply feindishly difficult to establish as such.
There's also an issue that's relevant to all of this- whether or not an automata is Turing complete is not the same as the question as to whether or not it can support "life." There are decent arguments for this claim, but it is far from obvious.
First off, Wolfram's attempt to classify automata into four categories is flawed: it isn't obvious that every cellular automata falls into one of those categories and not all the categories are even rigorously defined.
Yes, David has a page about that topic.
I believe that life on Earth arose spontaneously. I also believe the galaxy around me is largely devoid of life. I reconcile these things using the anthropic principle.
I also believe that fundamental cosmological constants have values convenient for the development of life. I don't know if it makes sense to pretend that those constants could have had other values - it seems to me like arguing that e could have been 2.716. But it's certainly done. And again, the anthropic principle is sometimes invoked, as an alternative to, say, God.
Suppose somebody came up with a new theory of cosmological constants, that claimed that only certain values are allowable, and that a large percentage of the allowable sets would make life possible. Then you wouldn't have to use the anthropic principle. Wouldn't you be more comfortable with that?
But if that's so, doesn't it mean that you really attach a low prior to the anthropic principle? And that you don't truly accept the anthropic principle?
How do you do Bayesian belief revision when one of your alternative hypotheses uses the anthropic principle? Can you give a strong preference to the hypothesis that does not require it? Because I know that I would.