To be honest my impression of slayer was not that he was hyper skilled but more he was a bit like Egwene after her first few lessons with the wise ones. He is experience in the world of dreams so he knows some of the pitfalls but Egwene was jumping around all over the place when she was there in TSR even before she got any training. Simply knowing that you can do this does not require a bit of skill, just some experience.

Slayer was dangerous in the world of dreams becasue he has more experience that most people with the exception of the dream walkers. What makes him really dangerous is that he is good assassin. Perrin was not as good an assassin but he had hightened instincts and better control.

Also as has been said Slayer seems to go there in the flesh and the Wise One told Egwene that going to the world of dreams in the flesh limits your ability to manipulate your surroundings to an extent.

As far as killing the wolves, yes the wolves are just as experienced as Slayer but wolves are at their best when hunting in a pack where as Slayer picks them off individually. In the world of flesh a wolf might have hightened senses over a human and be more agile but that does not mean that a hunter can't kill a wolf.