At least two of those examples are already in the weekly challenge log:
- Complete 5 FATEs with a gold rating, and another for completing 10 FATEs with a gold rating. Both award gil and XP.
- Completing 5 Beast Tribe quests, and another for completing 15 Beast Tribe quests. Awards gil for each.
The challenge log is actually fairly extensive, covering a wide variety of bonuses. Nearly all of them award gil, with the only real exceptions being those for Gold Saucer (awarding MGP instead); most combat-related ones award a decent chunk of XP as well. Most challenges have two or more stages, or have concurrent objectives. There's even sizable gil bonuses for completing multiple objectives in the challenge log each week.
So... the additional objectives are already there, the only real difference is how they are presented to the player.
"World Quests" in WoW were generally an
"in your face, DO THIS NOW!" sort of thing; that'd be too intrusive for FFXIV, and would likely push the game towards a more goal-chasing model that would hamper the experience for many.
How FFXIV handles them is
"here's something for you to do, if you want", giving the player the agency either do them or ignore them as they see fit; though I guess some may have some difficulty finding it, as the log is unlocked through an optional sidequest relatively early on during ARR. Heck, most of the rewards aren't even that big or important; so they're not going to become a domineering factor in everyone's playtime. The only real downside is that you have some players meandering about because they aren't being given an objective to chase by the game, and quite frankly the only solution for them is to either get used to the lack of direction or find a way to create their own objectives. On the flipside, many others enjoy the lack of something constantly pushing them towards completing various objectives; they
like meandering about and not having to worry about any sort of objective.