Ran around the tunnels with two other people on the pvp instance and got Catalyst to spawn in place of the champion in the heroic area. Took us about an hour, so we got lucky, but at least we know the spawn isn't bugged or anything.
I can't even give operations a shot, my computer is so bad that I can barely manage 20 fps with everything on low, nameplates off, etc. Same goes for warzones