I think a factor we can consider is accurate fabric in real life vs accurate-LOOKING material for the figures. Yeah, what you said made me think that runners like Usain Bolt and even gymnasts use tight clothing yet it works and moves like second skin. I was under the impression that more loose=more movement because I thought of ninjas' baggy pants, but then now I realize that it must be of different make and material compared to Batman's suit.
Yeah, I guess baggy crotch wasn't as noticeable on Spidey's as his legs are also thinner, making them looking long and still proportionate even with low pants.
Anyway, looking at the pictures I'm really impressed most by how the abdominals seem to move like they're real muscles -- and it seems that HT is also proud of that. So credit where credit is due:
The Batman v Superman: Dawn of Justice 1/6th scale Batman collectible figure has started shipping worldwide and many fans were simply stunned by this Dark Knight’s final product!
Since the introduction of the Batman collectible figure’s prototype, Hot Toys talented production team has worked diligently to enhance the figure to best reflect the spectacular physique of Batman and his unique Batsuit.
In order to capture Batman’s muscular body frame in the film, our team members have devised an innovative method to combine the specially developed body with a unique tailoring of the Batsuit. When fans get their hands on this Hot Toys collectible figure, they can instantly feel the difference from other regular action figures as the chest and the abdominal will feel like human muscles. There is also no sacrifice of articulations as wide range of motions can be achieved while the muscle on the torso can also contour in very natural way that is absolutely unprecedented in any collectible figures out in the market to date.
Hot Toys is extremely proud of this Batman collectible figure that requires true dedication from our team and receiving the overwhelming positive response of the final product from fans. We will continue to make new breakthroughs to bring more truly amazing collectible figures to our supporters.