I don't know how to come up with a reasonable model for how people are likely to interpret words without accounting for the fact that people interpret words in large part by how they have been interpreted in the past. But I don't see how accounting for prior knowledge of word frequencies makes the model tautological.
In points 2-3. Obviously we're used to hearing things in a certain order, and tend to copy that, but the question is why we put things in a certain order to start with. How is a 'great X Y' any more concrete than a 'green X Y'? Obviously concrete things have size, but then abstractions aren't exactly known for their coloring either :-)
But "the question", as you offer it, is based on the fallacy that there is some underlying natural law to the way we use words. There isn't. There is no blank slate "to start with," no axioms from which everything else follows. Words have always been used in the context of how they have been used.
Therefore, any reasonable model of how people use words will have some representation of how people have used words. My model uses simple word frequencies, yes, but it doesn't predict that one modifier sequence will be preferred to another because "that's the way it is." Rather, it predicts a sequence will be more preferred because it more rapidly and more evenly converges on a meaning.
The original question was 'what is the rule for ordering adjectives [in English.]' The first thing you said was: How about this rule? Order the modifiers to maximize the product of their successive restrictive effects.
I'm saying that your observation people copy what they know is tautological, and tells us nothing whatever about the restrictive effects of a given adjective.
How is Order the modifiers to maximize the product of their successive restrictive effects equivalent to "people copy what they know"? The restrictive effects of a given adjective are an input to the model because that issue was never the question. The ordering was the question, and that's what my proposed model attempts to predict, given prior knowledge of restrictive effects. The interesting prediction it makes is that people prefer orderings that converge rapidly and evenly.
