I'm just trying to gauge what you mean by "Open World Content", because looking at past MMOs that I have played before with Open World Content not structured by FATEs... the only thing I can think of is random special enemies spawning in a very small area of a map where appropriate that are used as minibosses in quest objectives, and are often killed by trolling players to prevent other players from completing quest objectives through the act of kill-stealing.
FATES aren't all that disorganized. They usually all spawn in the same place, even if respawning does take a little bit of time. When it comes to FATEs like "Defend the Hive", there are many FATEs that chain together like that. There's one in Northern Thanalan that many people grind. However, why should FATEs like that be the only ones to exist? I mean, if a large amount of a certain beastial enemy shows up, how does one follow up on that? Do we raid their habitat and render the entire species extinct? I get that you want more sequential FATEs, but to call the whole thing disorganized because there are only a small number of those sequential FATEs in areas that people FATE grind in just seems silly to me.
And there are actually plenty of those sequential FATEs scattered all throughout the game world that people usually avoid due to either not being in an area where people normally gather to FATE grind for the most XP or for being too high in level for the level they're FATE grinding for. U'Ghamaro in Outer La Noscea has one, Coerthas Central Highlands has at least two, Sapsa in Western La Noscea has at least one, etc. It's not that there aren't enough of them, it's just that they're not in the exact same areas where people FATE grind and are, thus, avoided and not common knowledge.