It looks bad for a number of very obvious reasons, but for me his hair annoys the most. Does he gel his hair and then put on his mask, or does he put on his mask and then get his hair around it?
Well, this is kinda what I expected from a proto-Bane. My understanding is that Gotham's origin of the character gives him ties to the military/air force, so the costume ties into that I guess. Still don't particularly like it, but I'm willing to withhold full judgement until it can be seen in full context.
The Suicide Squad has a tentative release date of August 2021 according to THR. That puts a Guardians of the Galaxy 3 release at 2022 at the absolute earliest.