The Linux iwlwifi driver uses less retry attempts for management frames, as in the diff below. I think it makes sense to do likewise.
Index: if_iwm.c =================================================================== RCS file: /cvs/src/sys/dev/pci/if_iwm.c,v retrieving revision 1.92 diff -u -p -r1.92 if_iwm.c --- if_iwm.c 22 Jun 2016 11:32:12 -0000 1.92 +++ if_iwm.c 22 Jun 2016 13:15:38 -0000 @@ -4381,6 +4381,7 @@ iwm_tx_fill_cmd(struct iwm_softc *sc, st /* for non-data, use the lowest supported rate */ ridx = (IEEE80211_IS_CHAN_5GHZ(ni->ni_chan)) ? IWM_RIDX_OFDM : IWM_RIDX_CCK; + tx->data_retry_limit = IWM_MGMT_DFAULT_RETRY_LIMIT; } else if (ic->ic_fixed_mcs != -1) { ridx = sc->sc_fixed_ridx; } else if (ic->ic_fixed_rate != -1) {