I lost two games to OBR yesterday - Three Places of Power and Duality of Death. Looks like Duality of Death is autowin for OBR against seraphon. If you don't have turn 1, it is already game over. You'll find 10 horses (30 wounds, 3+ save, 6+ fnp) on one point and 2x20 motek guard on another one. Scoring is progressive, so even if you can remove one of these threats in two turns, you are still on losing side. And if you have turn 1, then, well, you'll get a couple of points and just removed in a turn or two. I could say "screen with skinks" but Deathriders ridiculously mobile. Heck, they are faster than freaking ripperdactyl. But above all is their catapult, which will just remove the scoring hero in turn 1. Katakros eats your CP, which you could spend to reroll saves from catapult shooting. And 2 failed saves always = death for a hero. On top of it, most of standard ossiarch list is heroes and battleline, so they can score with any unit and each of them is extra durable. Sorry for the rant, but I hate this feel of not being able to do anything. By the turn 5 he only left with 10 riders and 20 mortek (thanks to hysh and its Banishment. If only I didn't roll double 1's for it twice) and I lost only 3 knights and a single razordon. But the final score was 14-2 in his favor. Usually this is what happened with me - nothing survived but I lead in points.
Tbh, I don't think, that plans like this one or total commitment should exists. GW wants to force more flexible lists through different mission coniditions, I suppose, but it ends up only favouring armies, which already has suitable armies composition.