Up B angled down when you are in the air and your opponent is grounded, or to a less extent UpB angled horizontally may surprise your opponent and it is a good kill option. It saved me more than once!
In fact, Wolf has a lot of kill options higher than 150% against many characters : smash attacks of course but also upTilt, Upair, Bair and even FTilt and Bthrow. Dash attack also kills at high%.
IMHO the problem with Wolf is that, compared to some other characters, he does not have many options to kill early. Dsmash near the ledge may be his best kill option at mid-high % but it is not always easy to land. Fsmash is almost useless IMHO because it is too slow. Angled up B is an option that grows on me because it may surprise your opponent (especially downwards) but it comes out a bit slowly and is highly punishable. Side B is deadly but difficult too land and very situationnal. In addition Wolf is quite limited off stage due his poor recovery. It is not easy to spike with Dair, because it comes out a bit slowly and again due to Wolf's lukewarm recovery. Clearly there are many characters with much better spikes.
Overall I really enjoy Wolf and he is my main, but I think that there is still something true in the "Wolf struggles to kill" meme that we heard a lot not long after the game was released. Not saying it is a bad thing because even with that weakness he is still a very strong and easy to pick up character.