[none of these characters make any sense with machine guns, not even Deadshot]
Add to that: none of these characters are known for flying, swinging, using jet packs, etc. This gameplay just has nothing to do with any of them.
Yeah the real story here is that it took Rocksteady seven and a half fucking years to get this game out.
I admit I'm biased and want to believe in Rocksteady, but let's not pretend in the post-Kickstarter era that evil publishers aren't the ones fucking everything up. This would not be the first time Warner Bros. pushed their noses in like a derailed freight train crashing through reinforced concrete and said something like "Let's do the thing that is money because money. Can we have RMT loot boxes? The kids love loot boxes. And jumping a lot! What about guns, make sure there are lots of loud guns. No this isn't stupid enough, you have to add in game billboards you click on to give us money."
I guess a bunch of important creative people left Rocksteady so maybe the leftovers are indeed the jerks here; still, that's not the first place I'm inclined to point fingers.