There's a DPS race with Yun Rau ?
Anyway i guess to go through you'ld still need a few epics from khitai at least for the tanks. The tactics aren't all that simple so figuring them out in a few hours on all 6 boss and then managing to get them right might take a lot more time than a few hours.
The Disco boss takes massive damage, if everyone pays attention and doesn't heal him he goes down very fast (roughly three aura shifts per 25%). It's fine in my opinion. Yeah eventually pets could take the buff but still doesn't take much for necros or demos to just play on boss without them. The dps needed to get him down is low.
But i agree on the Unknow completely. The bats teleport all other the place seems they have location issues and they reset a lot too. If that's fixed, especially the first issue, it would be perfect.