Actually, it depends on the number of people who participated in the previous spawn. Meaning if it was zerged by 50 people the last time around, mobs will have insane HP and the conditions for Gold will be pretty much impossible to reach. Together with the new dungeon XP and bonus XP from using the Roulette, FATEs should drop down in popularity quite a bit.

I'll be interested in seeing how one person will now be able to solo some FATE when no one participated in the previous occurence. Not that it was I possible to do before (especially for summoners) but it was hard with those FATE compreised of a single beastie meant to be fought in a party.