It’s obviously a failure on their end, but I believe it was a 100% intentional failure. A game that has made all of its profits by capitalizing on RNG, of course they’re also going to include RNG in their “fix” for duplicates. And they could say, “look, we fixed it! You now have a chance to exchange a duplicate hero for something else!”
“But I keep getting duplicates still?”
“Yeah, well, it’s just a chance. RNG is an integral part of this game. Keep at it long enough and eventually you should get something different! Maybe! But no guarantees!”
That’s how they operate. When they say they are going to “fix” something… heh… be wary. Like how they “fixed” the Telly/Vela issue? Or how they “fixed” the issue of Apple overcharging customers? Surely you didn’t think they were going to offer a way to actually get a guaranteed good hero for free? Madness! You must still pass the RNG wall. Maybe just 5 or 10 tries if you’re lucky. More likely it will take you dozens of retries, since the overall odds still heavily favor S1 results.