As if waiting up to 15 minutes for a group in solo queue isn't bad enough, you run the risk to be paired with a host/players with extremely poor ping, causing players to teleport around, rubber-banding, and an all-around a bad experience, and your only option at that point is to suffer through it and waste your time, or leave and receive a penalty. It's literately a lose-lose scenario no matter what you do, all because something you have zero control over.
As such, I suggest you implement a region lock, to minimalize the risk of getting grouped with players on the other half of the globe, and secondly, you need to be able to view other peoples ping in your lobby before entering the game. If anyone is in the red, you should be granted to leave without getting penalized.
I also suggest you implement a system which automatically detects which player has the best internet connection and make him the host. I have 1000/100 connection, and yet out of a dozen or so games I've played, I've only been the host once, despite my top of the line computer rig and ridiculous net.
