In theory and in execution this actually works really well. It also means that you can switch to another, lower rank to help a friend level, while benefiting your own advancement. This is one of the few bits of the game that really succeeds, but it's depressingly hampered by badly-executed systems and restrictions.
Where World of Warcraft splits at the seams with quests, FFXIV requires you to fish them out like cockroaches. They're predominantly found in the form of Guildleves, shorter quests that grant you experience, loot and Guildmarks (used to buy skills) both for the classic "kill five miscellaneous creatures" and for crafting quests. These are relatively fun but quickly become repetitive though they do remain satisfying in that hamster-ball MMO manner.
Combat is very close to the norm hit number keys to execute ranged or melee attacks, heal, or buff yourself or others. As you level, the animations and moves become more intricate, the damage more potent, the heals stronger and so on. As you gain strength in different jobs, combat does improve, but only insofar as the system allows.
Crafting is hampered by the sludge of the UI. You equip a tool, hit Synthesise, select the bits to use, select the tool, select the recipe, confirm the recipe, and then enter the mini-game. A little bar slowly counts down, and you get to choose how ballsy you want to be with your synthesis Standard, Rapid or Bold.
Bold ups the quality of the item, but is a gamble against its durability so you are mostly trying to up the quality of the item before you break it in two. This is fun at first, especially when it comes to meeting certain criteria for a Levequest. Eventually, however, requirements are such that you just have to find people to help you find bizarre items and this, combined with the relative difficulty of quality item-making, makes the process rather disheartening.
To add insult to injury, there's a limit to what you can do each day. The fatigue system in FFXIV stops you from making progress after a certain point. Essentially, you can only do eight Guildleves before your 'fatigue' significantly drops the amount of experience you earn, and the same goes for skill point gain. (It's explained very eloquently at Linkshells). This can be dodged by changing disciplines, forcing power-gamers to switch jobs and try out multiple parts of the game.
My verdict? Make your game fun before you begin placing arbitrary strictures on the players as to how fast they can play it. This is not World of Warcraft. This is a game that puts enough barriers in front of players as it is, and Square Enix should be doing everything it can to encourage them to play more and enjoy themselves, not to slow them down.
That said, the developers have done a good job of making FFXIV more approachable, systematically at least. Quests are soloable, and it's plausible to spend a fair amount of your time doing so. You will, because the communities are a fractured mess considering that the European, Japanese and North American markets share servers, areas are eerily quiet before exploding into textual diarrhoea as one random person tries to sell something and another spits kanji through your textbox.
This leads me to the auction house system, which doesn't exist, making player-trading a case of spamming trade chat in the hope that you'll catch someone. You know which other game didn't have an auction house initially? EverQuest. Released in 1999. Which then got an auction house added in an expansion pack in 2001. You can retain your own personal store-front NPC salesman, and apparently you'll be able to have multiple salesmen in future.
It's asinine that such a feature as an auction house is missing, and that's the theme of Final Fantasy XIV missed opportunity and a lack of understanding of fun.
If you look beyond the glaring faults and the barely penetrable interface, Eorza is a world seeping with charm and character. It has that otherworldly beauty of the series, and the character designs, while essentially rehashes of FFXI's, are attractive. Graphically, despite some frame-rate issues, it looks the part while avoiding the cookie-cutter designs of me-too MMOs.
However, content runs out quickly and the levelling curve is a brutal mistress. The Linkshell player associations can pursue their own guild quests, but these dry up. That's symptomatic of every MMO when it gets viciously pounded by the power-gamers but the problem is that, while other games flesh out dungeons and other content after release, FFXIV is left fixing base functionality.
Somewhere out there, there is a player this game is perfect for. But he or she would still be advised to wait another six months before even thinking about Final Fantasy XIV, because Square Enix hasn't yet got its head around its own players.