I don't think we need settings for master IP and port -- these are intended to be configured in spark-env.sh as general cluster configuration, as a convenience to users running ./spark-shell inside a preconfigured cluster. The "master" setting itself is probably worthy of being upgraded to the "Basic" options, since it's pretty central to the shell's functioning.

It might also be worth noting the default behavior is local mode, or SPARK_MASTER_IP if it is set.