Actually, I'm starting to realize that myself at this point. :-? From where I stand, I don't understand all that clearly what it is, exactly, you find problematic with mediopassive
read.
I know it has something to do with
read being, to use your words, a mental activity, but I don't get why that is a problem.
If I'm not mistaken, the problem is this:
Agent (I) - works change on (wash) - patient (the clothes).
With a book, no change is worked on the patient. If the clothes are clean after being washed, what is the book? The only thing it is as a result of being read is "read" (familiar, etc.). But that "change" doesn't reside anywhere in the book; it's a property of the reader, not the book.
So, while the clothes being washed undergo a change, in the case of the book, it's the reader that undergoes the change, not the book.
If this is what Andrew means by it, I think I see the difference. But I'm not sure how this difference is fundemental, in a way that it should prevent people from saying "the book reads well." The data suggests people either don't see the problem, or don't find that it gets in the way.
I think the problem lies with philosophy rather than grammar:
Given the wording here, "to produce a certain impression on the reader", the first thing that comes to mind is who or rather what is the semantic subject, the thing producing the impression. It's certainly not the reader, the person, nor is it 'the book' per se - Andrew's intuition speaks loudly, and tenatiously, against that. So then, could the true subject of mediopassive read be a projection or extension of the verb phrase itself;i.e., The book reads well means Reading the book produces a good impression on the reader
How do we frame the difference between the book (physical object) and the book (ideal object)? I might say I've "read the book" if I read it on screen at Project Gutenberg. I might say I've "read the book", even if I read each chapter in a different format (chapter one - on screen, chapter two Audio-book [read?], chapter three library...). "Book" is both the medium and the message.
The book burns easily. vs. The book reads easily. "The book" isn't semantically equivalent (An electromagnetic pattern on some hard drive might compose a readable book - if translated by appropriate technology, but it doesn't burn easily.)
There may be world-views/philosophies that work against "The book reads easily," but mine doesn't, mostly because I can conceive of a book independent from either the physical object, or the psychological re-presentation (I tend towards phenomenology). If I tended to more idealistic or realist points of view, I might find the usage strange, too.
Am I making any sense?