I'm a museum poser, but even in museum poses, ab articulation helps in making a more natural neutral stance, which can also help in giving balance to the center of gravity, making figures stable even without the aid of a stand.
I really want this figure, but even after seeing the reviews and the figure on display at a local shop I still can't get myself to really love it. Even standing there, yes it looks good, but you know it's not constructed as the other IM figures you have on your shelf. That swap-out ab system is not forward thinking for me, as if it's made to make the ground pose perfect. I can't help but think that it's made this way because it's the same thing hangin in chains on that construction version release. Everybody talks about the shoulder gap, but in Xenomorph's reviews you could see that a gap between the waist and the pelvis can be seen, and that's because you really have to make the ab part sit flush, something you shouldn't be doing if it were a well-engineered figure, like the previous releases.