Re: Aikido spear- Aikiso
And when there is more than one attacker... Like someone behind you...
The point for me is that it isn't an issue of obviously the yari itself (or naginata for that matter) being the bladed end, but in most styles I've seen they rather actively train on using both ends of the haft. Which is why there's an ishizuki in the first place and such a huge variety of styles depending on ryu/regional style/etc. Color me puzzled...
And yes, some styles of swordsmanship also have strikes with the kashira. And there are a few rather rare types of kashira with "pointy bits" ostensibly for that very purpose. But it's no where near as common as in yari work in particular.
And for that matter you should see the incredible variety of styles of yari which also impact how they're used. You're not going to use a tanpo yari the same as a jumanji yari or a kagigata. And if you want to talk absolutely vicious look up futamata yari.
And on the point of regional differences, the kagi yari also has an iron "sword catcher" about a foot down the haft from the yari blade itself. The applications of the weapon are going to be clearly different.