No, not intended to be a criticism at all. It is a beautiful book. Not one of my favorites, but an excellent book, especially on the first read.

My point was simply that, to a degree, the characters themselves are tools for that emotional impact the book is building towards.

I like Lenny and George. But they don't feel alive to me the same way that Lee or Sam Hamilton or the Joads feel.

Ultimately, my point is merely that if OP likes the characterization in Mice and Men, where the characters are hampered by their need to fit in the box, if you will, of serving the sharply defined goals of the book, then he or she should like the characterization from Grapes of Wrath or East of Eden even more.