hping3 is a highly flexible and versatile ping utility, see here:
hping3 is particularly useful for SQM-related applications because it offers inter alia a timestamp-based ping (icmptype 13), which facilitates one way delay calculation (i.e. determine separate uplink and downlink delays, not just the bidirectional RTT).
No doubt there are other use cases that would benefit the wider OpenWrt community. Such a versatile ping utility certainly feels like it belongs within the OpenWrt toolbox.
And @_FailSafe wrote an AWK parser to parse its output to give one way delays - code available here:
Can any generous spirit help get hping3 made an official OpenWrt package? It used to be at one time apparently, and hopefully the effort involved would be lessened given this fact and also @Lochnair's work on this so far.