Since the most recent change I am totally unable to gain any IF above the passive cap while using even a single form. Previously, if I were only using dragon my IF would very slowly increase; it would take > 1 hour to fill, but it would increase.
I ran a test today. I started by fighting without anything active. After a half hour I was at about 50% above passive cap (nearly your full height above you). Then I turned on dragon and continued killing as fast as I can. After another half hour my IF had decreased a notch.
I know that there are abilities coming out soon to help with IF gain, but I wanted to note this because the recent change didn't indicate that IF gain would be worsened.
177 IF, 155 Aug if it matters.