A lot of people in the other thread are bothered by any mention of anything wrong with the figure at all, so those of us who see the need for any mods have had to tread lightly.
The height is what brothers me the most, as it's so very basic and not subject to artistic interpretation as is the sculpting, including that of the helmet. But yes, it's off. You already mentioned the size, plus there's the width of the bottom rim as well as the top of the dome. It doesn't even have to be combined with the mask to see the issues. However, the neck and helmet position mods seem to mitigate this somewhat and it appears adequate and even good in many photos.