So did I. Personally, I think he suffers from too much of his own brand of categoricalism.
I reject an awful lot of his rationale for things while finding some merit in his linguistics. His method tries too hard to assign unintuitive meanings by plumbing a wide variety of ANE sources.
Jack Collins says “It is a mistake to identify the views of Genesis with the views of Israel…Moses sought shape the worldview of Israel, not to echo it.”
Tod Beall says "Now, to be sure, I think Walton makes some good points that do help us see an emphasis on function in the creation narrative. But then (as in his use of the ANE sources) he goes overboard, insisting that the text says virtually nothing about material creation. Even scholars who are somewhat sympathetic with Walton’s views say he has gone top far, here. [Footnote 44 cites Waltke, Gane, and Jack Collins, who says “Walton’s distinction between ‘function’ and ‘material’ may be useful for analytical purposes, but it hardly warrants the kind of separation that he advocates.” --see Collins’ review of The Lost World of Genesis One, section 4]
For further exploration, see “Reading Genesis 1-2; an Evangelical Conversation,” ed. J. Daryl Charles, Hendrickson Publishers, 2013. Walton has an entire chapter in there; chapter five, and Beall’s review, among others, is there, too.
All that said, Walton has made observations on linguistic grounds which are not affected by these issues, and his interpretation of the “forming of Eve” story is NOT considered outlandish or beyond the pale; quite the contrary --it is a proposal worthy of serious note. Too many evangelicals hear something a little different, and decide to throw the baby out with the bathwater, without bothering to reason things through.
Hope that helps; I am, by no means a “Walton devotee” --even though he has his share.