Lol. Combat has nothing to do with this. Competing on the combat aspect is a completely different pair of sleeves. Guildleves are just a repeatable quest system, it can't get much deeper than this. People expect story-based experiences. Guildleves are a good filler, but will never be more than filler.
Firstly, Guildleves can be randomized like in Nyzul. They can implement a ladder-style progression to it (like progressing in the ranks of the three factions), where you get to fight bigger monsters and tougher(looking) bosses. They can be made a part of the garlean invasion by having your performance judged by the game and making the garleans either defend or attack accordingly dynamically. More objectives can be implemented. Random events between NPC's or even humanoid mobs can be implemented that flesh out the story in the leves. Efficiency can be made more rewarding, giving people a reason to try to get "a high score" during the leve, like more SP. Random buffs and debuffs can be added to make things more interesting. And that's just what my imagination can come up with.

You are making yourself look more and more ridiculous by saying "guildleves can't be more than they are". It's like you are looking at the world through your own narrow glasses that only see what's in front of you, not what could be. Guildleves are a template, a Tabula Rasa, and SE can do anything they want with the system. It is simply full of possibilities. Full of them.

EVE online has an original lore, Both are compelling and deep. BEsides, "tend to suck hard" is an entirely debatable and arbitrary evaluation of yours.
Excel Online has original, good lore? Was it behind all the math and technical info the game throws at you?

Those who don't think the lore sucks live in a denial or are fanboys. Simple.

The lore is interesting but it's presented in a WAY too diluted way towards the beginning of the game. The same comes for the guilds. You're simply thrown into a world of which you know basically nothing (and your character decidedly isn't a kid), and remain blindfolded for a long time before you start to even see a bit of light. That's way too little too late and fails at keeping new players hooked until the "good stuff" comes.
Hell, I don't know about you but I was presented with background info about Archons and the coming invasion of Garlean empire at rank 5. It will only get better once they add more to it.

I already gave plenty. This game may beat them from my personal point of view, but it's doubtless that many other MMORPGs in the markets have a very good lore, that definitely is on par, competition-wise with this.
Well, why aren't we getting any examples? Excel Online? LOTR "HEY LOOK, OUR GAME HAS GANDALF" Online? Rift "Our game is named after our novel new gameplay feature, see how serious we are about the lore? LOL!"? Age of "Hey isnt this world cool? Not that there's anything to really look forward to, but HEY LOOK IT'S" Conan? Aside from WoW, every game fails hard lorewise, one way or the other.

Actually, since one of the most criticized aspect of the game in reviews is the very weak lowbie content (which is the only thing most reviewers play, by the way), and reviews DO influence a game's success, yes, it's fairly safe to say that it had a LOT to do with how the lower levels are setup.
Which is why a) tutorials and b) guild"this system can't be made any better"leves must be implemented and fleshed out. But because we can only look at the present situation (where there are a lot of sidequests to do already), we can not figure out a situation where things would be different without doing exactly what the OP proposes to do. Oh wait, that's not "we", that's just you.

LOL. There's no audience that's LESS appropriate to a sandbox environment than the Final Fantasy one, that comes from SINGLE PLAYER games on consoles.
Yet the FINAL FANTASY audience has been craving for all things sandboxy since what, FFX?

Just like "there is no less appropriate audience for FPS games than the console audience". "There's no less appropriate audience for MMO's than the RTS audience". Oh wait, how'd that go? But yes, keep LOLing all you want.

Selling the game to the Final Fantasy target audience means selling a strong, dense story-driven product. Not a sandbox with repeatable miniquests.
Cities! Open world you can explore! Sidequests! Towns full of NPC's! Did you not hear about the criticism of XIII? That game can't get any more dense storywise, yet somehow the audience was asking for the aforementioned things. Hmm.