Changing the character designs wouldn’t require an all new game. If they can come up with a signature gamemode and better characters, they could have some moderate success.
TBH I had a look at Deadlock’s characters as well and frankly they’re not that inspired and interesting either, but people really like that game because of how it plays. Still that’s in early development so the characters could improve. IMO if the Concord devs make the characters hot, people will pay and play. I’m not saying that’s a good or bad thing, just what I think.