Wrapping up SKY FC finally. Clock time is 42 hours currently. Finished the Royal Villa section and going into the sewers now, so it feels like I'm in the endgame.
Been trying to do the game mostly FAQ-free (I wasn't trying to get all BP) but I've heard so many things about the final boss and dungeon I'll probably look up how to have my orbments and team set up to avoid major headaches and avoid getting trapped into points of no return, and just power through to put the game to bed for good.
I've decided I really love the game, but it isn't a very easy one to love at times.
For Orbments, speed is the most essential stat to boost. Then, tinker with the Orbments until you can cast Earth Wall with two characters, making sure that those two have both Cast 2 and Action 3 equipped; since Estelle has to be in your party and she isn't very good, she should basically just be an Earth Wall tank (this will apply to Sky 2 as well...and Sky 3). That's basically all you need to do to win the late boss fights in the game, assuming you're playing on Normal, as casting Earth Wall repeatedly will mean that enemies cannot damage you. Personally, I used Estelle, Joshua, Kloe, and Olivier. My strategy was for Estelle and Olivier to cast Earth Wall and heal, as needed, while Kloe and Joshua used attack magic; I gave Joshua a Gladiator Belt so that his amazing S-Craft would charge automatically, and I'd have him use the S-Craft instead of magic when possible.
Sadly, the final dungeon in Sky 1 will require you to fight a ridiculous number of awful chest battles. These chests are, unfortunately, the only way to get most of the best equipment (aside from Estelle and Joshua's best weapons), and they also give a lot of experience points. If you fight those battles, just spam Joshua's S-Craft, taking advantage of the Gladiator Belt, and cast White Gehenna as often as possible (the chests contain evil enemies that can cancel Arts, so Joshua's S-Craft is the most reliable source of damage against them).
It's good that you love the game. I think it gets better as it goes along, but I never loved it since I think it's mediocre or worse for too large a percentage of the game (I am a big fan of its NPC dialogue, though, which is the only area where I think Sky 1 truly excels).