You can't actually fault Zack Snyder and Warner Bros. for their out-of-the-box thinking when it comes to casting. And, when it came to Aquaman, it was such an unusual offer that it wasn't even close to what Jason Momoa thought he was being called in for.
For all of its other problems, most of the casting in DCEU has been very interesting. Most of the time, it's worked out. Both Gal Gadot and Ben Affleck were met with questions - his more reasonable than hers. But she's been a ray of light in every bit of footage we've seen. And many reviews described Affleck's performance as one of the least bad things in Batman v Superman. Will Smith was the most likeable he's been in years in Suicide Squad.
Similarly, Momoa didn't think he was in the running to play the very blond-in-the-comics character Aquaman. In an interview with ET Canada, Momoa described his thoughts when he met with Zack Snyder:
There was a lot of things that went through my head when he said "Aquaman." There were a lot of things that went through my mind. 'Cause I was thinking like "Lobo." I'm gonna play some kind of bad guy. I'm like, "Who am I gonna play?" And yeah, he said "Aquaman." I was just like, "Come again? Pardon me?" And then he explained why. I was like, "Whoa, buddy. I got your back."
While the consensus among us is, "Yeah, he would have been a great Lobo," Momoa's performance in the Justice League footage has done a lot to fix the average person's perception of Aquaman as "man who talks to fish".
Yeah, definitely rehabbing his image.