Right, people scoff at North Korean presence, but I doubt the North Korean soldiera would be used in human wave tactic as the Russians do. North Korea is still an independent sovereign entity, and the last thing they want is to let their troops be used by Russians in a shitty way. It obvious that North Korea will want to gain combat experience, the same way that South Korea sent troops to Vietnam fifty years before.
Of course there is more tit for tat deal, but North Korea will not send troops to combat if they think they will not gain anything from it militarily.