Sadly, I agree. Even in the scenes when I suspected it was Mayhew (i.e., not much physical movement) that old "familiarity" with the character just wasn't there. And whoever it was that doubled for Mayhew, I didn't see any attempts made whatsoever to mimic Mayhew's body language.
Also, regardless of the fact that the original mask didn't have much articulation, Mayhew managed to emote through it by use of certain head movements, and that was also lacking in The Force Awakens. Except for a passing resemblance, the Chewbacca I remember from the Original Trilogy movies wasn't present in this one.