Yeah, NECA does do a fantastic job at capturing a character's expression and emotion in their sculpts (ex: Smeagol, closed mouth predator, Penguin, Hulk etc). But sometimes, their sculpts can just be straight up awful too (MOS Superman, Tony Stark Ironman, unmasked Captain America). It's usually their human sculpts that are bad.
I don't have any of the Arkham Batman figures, but everyone that has one seems to really like it. You should just get one and mod the hell out of it. That's the cool thing about NECA figures; they're so affordable (compared to hot toys) that they won't set you back too much and also, you don't have to be so worried about ***king them up when you mod them. Based on how your modded MOS turned out, you'd probably be able to make NECA's Arkham Batman look like he came straight out of the video game.
Edit: I just checked out the NECA Arkham thread and saw all the awesome modded figures you were talking about. Was the battle damaged one you mentioned made by Heubert?
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You're right, it does look like a high-end HT or Enterbay figure. The battle damage and neck mod really take it up several notches. Awesome job by Heubert!