Fervor V. Warlords for ADCs

Throughout the prepatch I've seen Warlords more than Fervor in the bot lane and I believe it's for the lane sustain. I also read the possible changes to fervor by increasing it from 4 seconds to 5 seconds. A way to buff fervor in my mind w/o increasing its damage is to lower the price of Dorans Blade by 50g to allow ADCs to gain 2 Health Pots. Where it might not be as great as Warlords sustain it will help with fervor to keep up with Warlords at least in the early laning phase. Ideas to why this change could be a good or bad idea?