You can't compare Ben Affleck to Zack Snyder.
They are much too different to attempt it. Comparing them is almost as pointless as comparing, say, Michael Bay and Woody Allen.
They are two VERY different directors, with two VERY different styles, and two VERY different filmographies.
Both have things that they do phenomenally, and things they don't. And they both have things they're weak at.
Now, did Affleck's clout at Warners (following his success with Argo) help his case when recommending Terrio? Definitely. That said...... I don't think that because Affleck is what some, like you, would perceive as a better filmmaker, that he has some unrestricted control over this project. At least to the point of making decisions that dont pass through Snyder.