The problem with that is that unless you want PvE targets to be completely scripted, it's almost impossible with current tech. There's pretty much no MMO that uses any significant AI because it would be too difficult for a server to process dozens or hundreds of instances using complex AI. That's why almost all mobs in nearly all MMOs tend to be the type that either just mindlessly stand around or walk pre-designated patrol routes until they are interacted with. Something like that could only really be realistically implemented in a small team game that is hosted on a computer rather than a centrally maintained server.
omg no, I hate you people, I keep explain THIS ISN'T THAT HARD. It has been done before on hardware ten years older than what we have.