The current method works fine. The only time I see remaking a game as problem is during PTR. And if there is a 2 Hour or longer one, the exiting of the game opens the queue to others in the queue. So I don't see them fixing this.
The issue with public games is an issue. They have eliminated the 30 second timer but retained it for regular ones. This is because of loot and blood shards. If someone closes it gives you time to run back to town and make room for these items. GRs have Urshi to block the close, if you leave loot or shards, you just don't talk to Urshi.
While it does seem like a good idea to just add a button to forfeit, but, what is the mechanic to block it? GRs close immediately. Currently people just leave public games and remaining players continue without them. So what would happen if they could close the game? The others would forfeit their keys. So asking whether they they should implement a game mechanic without stating that the new mechanic is just as problematic is silly.