We're complaining because characters we like are being thrown under the bus, or likely wimpified, for the sake of Harley.
Now that Ant-Man, Aquaman and Guardians have proven to be successes, I think we can do away with the fallacy that comic book movies require a 'big name', both in character and actor, to succeed.
This seems like Suicide Squad 2.0, relying on both to the determent of the rest of the cast