Hey guys as I already said on the official Leech's thread I got an answer on FB from the Four Horsemen about him neck:

You're seeing it from a bad angle in that photo, but we had to do the neck area the way we did so it wouldn't.
Hinder movement of the head. Also, it looks as if they may not have the head pushed all the way down on that prototype, so the neck articulation's not in place yet.
The head you see there is currently just attached with a chunk of clay shaped similar to a rod so it can remain somewhat posable for photography or display.

-FH-
So I don't want to keep debating about Leech, it's more about showing our appreciation to the FH's awesome job because many of us may have misjudged Leech.
In the future, maybe Mattel's people should try to use more care and attention when posing these porototype for display, to avoid this kind of issues. Just take you time when posign them!
Thanks