I thought his performance was decent. My only issues with him were: 1. that weird twang he tried to do with his accent and 2. how he was written in certain spots. Regarding the latter, I don't think they intended to make him look like he sucked at his job, but he really did. First, he apparently immediately falls in love with a woman he's supposed to be protecting, and I guess this is a regular thing for him since Waller somehow KNEW this would happen. Then he keeps nearly getting captured by the eye monsters and needs to get bailed out by the team. THEN he loses control of the team. THEN he barely does anything in the final battle. Yet he's supposedly this total badass, decorated soldier. But like I said, I'm not sure any of this was intentional, since this is the second DCEU movie featuring characters who don't seem to know what they hell they're doing.
However, strangely, he had a decent arc and I enjoyed the bromance scenes he had with Deadshot. So the character was a bit of a mixed bag. I'm glad Hardy passed on this. He's one of my favorite actors and I feel like this movie, and perhaps the character, were beneath him.