Really? I figure there is some number of outsiders (non-cops) who will attempt to murder cops, for the same various reasons that have persisted for centuries. Wronged by the law, gang initiation, escape arrest, cop boinking wife/husband, and so on. And, much fewer in number, there is always a chance that an insider (a cop) will turn violent on his peers.
IOW, Dorner didn't create any new wackos, or any new reason for a wacko to attempt murder. He had his issue, and now he's dead. His issue died with him.
The very essence of copycats is that they are scatterbrained and spontaneous. The word copycat is assigned to them by the media after the fact. In real terms, they see some cop standing there, so they walk up behind him and shoot him in the head.
When asked why, after the fact, they just give a 50/50 of “wasn’t me” and “I donno.” They are too stupid to anticipate.