The criticism is lack of incentive to play FG because it doesn’t contribute as much as the base game or AoM to endgame components, and AoM has potion of clarity. I typically need significant amounts of ugdenbloom, battered shells, seals of binding etc. that when I level a character up I feel compelled to be efficient and farm along the journey to cut down some farming time later on. Even then the farming time required is still quite a significant number of hours. The result is that FG content is usually a late game activity.
I know it has transmutation and the legendary vendor but those are more niche whereas every character needs endgame components.
Lastly I know there is a solution called gdstash to let me play FG more but that doesn’t exactly feel good.
I would suggest adding potion of clarity to FG faction vendors and creating a vendor that sells ugdenblooms at the cost of iron and eldritch essence. Possibly add other important materials like battered shell? Something to remove this negative aspect of playing FG.