From what I've read, you level in two ways, weapon and character. Does this mean that your character grows in base stats, while your weapon stat is a proficiency one (higher the level, the more effective, and the more abilities you unlock on that weapon), or does your base level determine your stats with the weapon level only relating to damage... I assume the former given that you can apparently switch between weapons/classes?
From what I can gather, the weapon level will grant you skills and abilities tied in with the job you're playing, as switching weapons literally switches your roll. So if you are a Lancer, you are skilling up pole-arm and unlocking Lancer skills as you go. The character level will probably grant you higher HP, MP, TP and perhaps stats, but this time around I think the player has more control on what to specialise in. I heard also you can adjust elemental afinity. Like you said there is not a lot of info out there that explains it in any great depth, so all we can do is speculate.
What kind of ability system is in place as far as magic goes? Are only magic classes able to use spells, or can they be added to weapons (similar to the system in FFVIII)?
They have stated that you can have any job casting spells, all you have to do is unlock them. They want you to make a character suitable to your style of play and not like in FFXI where the only choice you had was really which sub-job you used and even then that choice was limited to solo play as no one in their right mind would invite THF/WHM for example.
What form does endgame take?
How many servers/region specific servers? I've seen some people talk about playing with Japanese players on XI, is there literally a global server (is that even possible)?
No clue on endgame.
Crystals will be your storage, but they have stated that the mog-houses may make a return in later updates.
And yes, global servers were in FFXI although you had no say in which server you were inevitably on, unless someone already on that server provided you with a world pass. Playing with people in both the US and Asia, I made some good friends and I hope the same system is implimented as I would very much like to play with those people once more. The auto translate made communication (when it came to party or raid orders) easy and in some cases a laugh. Galka Sausage anyone?
How useful is crafting; if I decide to sink hours into crafting that one weapon I like the look of, how long is it going to actually be useful in the game (because in most other games, drops are far better than crafted gear)?
Is item remodelling available?
Crafting was a very important part in FFXI, it was literally the backbone of the economy and I beleive the same will be said for FFXIV. They have already stated that Blacksmith is effective fighting against machine type monsters and that they repair armour and weapons, so expect crafting to play a big part in the game. As for remodelling... maybe. If items can be repaired, I can imagine them being dyed, not at release, but perhaps in future updates.
Vanity pets (ok, I just want a moogle running around behind me)?
Chocobos available as mounts? I also read something about chocobo breeding in XI, is that breeding for racing a la Golden Saucer, or is it for faster mounts?
I would love a moogle too! I was kinda hoping the retainers would be Moogles, but I don't think they are.
As for the Chocobos, they stated they are going to be used differently compared to FFXI, so I dunno if they will even be mounts. Breeding... I hope so. In FFXI when you bred them you ended up with different coloured birds and certain ones ran faster. Of course they were on a cool-down...
Ah, I don't even think I've helped that much. the only people who would know all of this are in the beta and can't discuss it. :(