Upon defeat you gain x amount of skill points which went into the dude's current weapon (swordsmanship), which is basically like AP systems of old.
Oh, that's not necessarily an AP system. An AP system allows you to customize how you learn abilities, and while it's technically accurate to call a system that only let's you do that much an AP system, a TRUE AP system lets you customize your ability configuration. i.e., Abilities are each worth a certain number of points and you choose the abilities you want without exceeding the total (where the term "ability point system" comes from). People around here usually liken it to the way Blue Mages can set their spells. Meriting in FFXI is a true AP system, though a fairly terrible one.The whole concept is that each ability costs a certain number of points to set, thereby allowing you to choose which you want, but with limitations.
Final Fantasy Tactics, for example, doesn't use a true AP system, but it gets to slide because you actually can customize your abilities, although not with point values. They called it an AP system and a separate element of the game is -like- an AP system. If you weren't able to set a secondary job and other skills though, it wouldn't even count as an AP system.
Point being, AP systems refer to the way you -configure- abilities, not the way you -learn- them.
Leveling up your weapon from killing enemies is just... a skillup system. Not terribly different from in FFXI except for what causes the skill to raise.
I'm still hoping that there's a real AP system, but so far that's not it.
Ok, now we're going to get slash fiction of Wint x Kachi somehere... rule 34 and all...
Never confuse your inference as the listener for an implication of the speaker.
Good games are subjective like good food is subjective. You're not going to seriously tell me that there's not a psychological basis for why pizza is great and lutefisk is revolting. The thing about subjectivity is that, as subjects go, humans actually have a great deal in common.