What traceroute and mtr have told us is that ICMP echo requests (called a ping) don't get there reliably, but that can happen for multiple reasons. Maybe a server along the path doesn't feel like passing your ping along and drops it. There's a point in their machinery which blizzard doesn't want you peeking past, and other companies might have their own reasons even if the route is healthy.
A friend says the game has two network sockets that have individual pings (latency measure this time not echo) and you can see them by hovering your mouse over the indicator. Which is it that's misbehaving?