He didn't learn his lesson from Conan

Great point. You can't carve your way in Hollywood by stepping in other people's shoes. He was definitely taught that lesson with Conan and he didn't learn. Aquaman is something he can truly make his own. I'm not sure why he's bothering with this film. Even if it's good it's just gonna divide the fanbase, both his and the Crows. He's sort of popular right now but i'm sure he's not getting flooded with movie deal offers. Probably has to take what he can get. But you don't want to get typecast as the promising tv actor who kept serving up sub-par installments of beloved movie series.

But, Bill Skarsgard did the remake of It and it was massively successful. His Pennywise has even become iconic in its own way (not to take away from Tim Curry's fantastic performance).

Conan is a role that could be played by anyone that looks the part like Batman or Superman. Besides, this doesn't star Momoa anymore. It's Bill Skarsgard.