I agree with that. One of - no, I have to say THE best sounding guitar I ever had was an Epiphone LP junior - and that was, indeed, plywood.
On the other hand, neck timbers - especially where they have vastly different stiffness characteristics, do in my view make a difference. But the difference in sound with different body timbers of a solid body electric, I am pretty certain, is inaudible to the average human ear.
Oh - and why do I specify 'solid body'? Simply because, against all of my perceived logic, I pin my belief to the mast that you simply cannot get a Gibson 335 to sound like a Gibson Les Paul, and you cannot get a Gibson Les Paul to sound like a Gibson 335. It's subtle, but it's different. Same pickups, same scale length, same neck construction...