I've gotten suggestions for "op" and "addr" as well.
There's a couple factors that I think are important:
1) We're using a flat structure for the request, which makes it easier to write; i.e. no "parameters" level. So, these become reserved words; i.e. can't be used as the name of a parameter.
2) We want it to be easy to create (i.e. type) requests, so I've shied away from real long names. Perhaps this isn't so important though. If people are creating requests using jboss-dmr, they'll likely use a constant or some utility and won't be typing "operation-target". Same with people using REST. And with the CLI, we can probably eliminate most of the need to type "op" and "op-addr" in requests.
Telnet? Hmm. We need to secure it. Right now it's a binary protocol, but it should be easy enough to develop non-Java clients for it.