warlords needs a little buff, its too weak compared to fervor.
Even on the optimal case (say playing cait with shiv and rfc) its still not worth it go it over fervor, it doesnt do anything in lane and its not good enough even with double shiv/rfc items because fervors just gives you the much needed dps, for like every adc.
It needs something extra, its power level is just too low, maybe adding a 20% slow for 1 second or something to the proc, so its still not about dmg/you give up damage for taking it over fervor but you can kite very well with it.