It would be really handy poll certain items from the server instead of the proxy like when you are using external scripts, or suppose you want to test the latency from the zabbix server to the host and not from the nearby proxy.  In my case I'm trying to test that 1500 byte packets flow from the zabbix server to the monitored system, but that gives me nothing if it sources from the proxy.

ZBXNEXT-1411 could sort of do this, because you could define multiple interfaces and assign the item to the interface that omits the proxy, but it wouldn't map to templating very well.