Thank you for your feedback. Today publishing NSG Flow Logs to an Event Hub is not currently supported natively. We will continue to evaluate this suggestion and update the status accordingly.
Today, if you are interested in transforming and streaming NSG Flow Logs to a 3rd party endpoint, we have published a sample here that leverages an Azure function: https://github.com/Microsoft/AzureNetworkWatcherNSGFlowLogsConnector
Splunk has also published a blog with guidance on integrating NSG Flow Logging data here: https://www.splunk.com/blog/2017/02/20/splunking-microsoft-azure-network-watcher-data.html