Jason Momoa initially thought he was being cast as Lobo...

[Hector]

...when first contacted by Zack Snyder.

Jason Momoa: "There were a lot of things that went through my mind. 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."

http://www.cinemablend.com/news/1582070/the-dc-villain-jason-momoa-thought-zack-snyder-would-ask-him-to-play?ref=yfp

He would've made a great Lobo...

[Starroid Raiders Dagon]

Way better in appearance than Aquaman for me. I would have loved to see Lobo on the big screen. Just wait until the movie hits and WWE tries to dress up Roman Reigns as Aquaman-lite!

[Bruce Banner]

Yeah, he should have been cast as Lobo, IMO.

[The Bat]

Now that would have made sense.

[PNGwynne]

Well, I don't care much for Lobo, but Momoa would have been better-cast as him--with Charlie Hunnam as Aquaman.

[Starroid Raiders Dagon]

with Charlie Hunnam as Aquaman.

YES! This would definitely been much better.

[Hector]

You can't blame Momoa for accepting the role of Aquaman though. What you expect him to do? Turn down the role? Heck no...

[PNGwynne]

No, no--I don't blame Momoa for anything, I like him. His Aquaman will doubtless be interesting--and fun. He's always intense and full of energy. But he's not my ideal casting, just saying. I hope he proves me to be short-sighted, I want the Aquaman film to succeed!