1) undying's flesh golems can't get through that choke point from the WK area towards the creep lane - having to walk around the ENTIRE MAP with those slow asses is not only slow, but you have to do it almost manually because they automatically want to go towards that choke point only to turn around when directly at it.
2) pressing necromonicon near some bosses summons like 10-20 of them and makes the game lag intensely.
3) teleporting with tp scroll towards (for example) AA or the Weaver, by default you teleport on a cliff where you can't get off without flying or teleport. Especially annoying when playing as UD because it makes you not want to have wings or tp boots
Bonus) blink dagger exists (for 0 gold, nice) but it doesn't work? At least you can't blink off from a cliff, that much I've tested. :p