Record number of ping requests and responses for TCPIP (By interface), as a network debugging aid

After reviewing your request, it is being rejected because we have determined that this is not something likely to be implemented. For the enhancement you suggested, it would provide data that would be hard to determine whether your ping made it in and out of the TCP/IP stack. For example, as you mentioned, other ping requests could be occurring at the time. Also, there is no guarantee that the response to the ping request will go out the same interface that the request did - so there would be the problem of trying to match up requests and responses across all the interfaces.
A couple of suggestions for troubleshooting a scenario like this in the future. First, use the traceroute command from a remote system to confirm that network connectivity is at least good all the way to the router serving as a next hop for the z/OS system trying to be reached. And second, you mentioned that using packet trace on z/OS is hard to do. It should be as simple as using the VARY TCPIP,,PKTTRACE command, and specify filtering options to limit tracing to ICMP messages "PROT=ICMP" to the IP address you are trying to ping "IP=ipaddr". Once captured, you have the ability to convert the packet trace so that it is viewable from wireshark, if you are more familiar with that tool than IPCS formatters.