Hammer should provide information about proxy status
To get parity with the UI, the command for listing proxies should display proxy status. The info command should display the status too, plus version of the proxy, number of managed hosts and list of enabled services with information about them (see "Services" tab on proxy detail page in UI).
Implementation-wise the info command should probably provide a way of extending the list of services so that a plugin could add custom fields and data for a service type (eg. hammer-cli-katello for service Pulp).