Okay, I'll add some brief explanation of some points I haven't expressed well before:
1. about Espastones:To be honest, in the beginning my mind screamed "OMG! This is FF6!" but later, when I read the .txt introduction, I've understood they were a more complex and elaborate idea. So I began respecting it, since you have found a really good background to explain their origins.
Materia + Magicite, you said... so are we going to see a materia-like system with some feature from FF6? I mean, items that allows player to learn magic but when removed leave them without any magic power? It could be a great system if well developed.
2. about the settings:The best setting I've ever seen was FF7's in my opinion. Midgar remained fixed in my mind and in my heart as a sort of symbol. This is my personal opinion, though.
I think RPG with FF6 technology level are too much diffused. I'd prefer a FF7 - FF8 like technology level. FF8 had a decent mix of nowadays technology (cars, gas stations, trains) and sci-fi effects (Esthar, the flying coliseum, Lunar Gate, Ragnarok).
If I have to be honest, I'd be for this kind of environment, though, it's only a personal preference.
3. about Lydia:Alas! Terra is too much a term of paragon when coming to this character! You really have to do something special to develop her personality. Anyway, you could do something like this:
Archadian Empire is too strong fo Nazara's army, so a direct military action to take Lydia back would be a suicide. Anyway, Lydia is unique, so they need to save her and take her back to Nazara.
It will be better to send a small group of people (two or three) who have nothing to lose (Vihana is orphan and has no family, so she's a good candidate. In addition, she knows Lydia; same for Sakia; Sven is a soldier who knows how to fight; as regards Desolo could simply decide to follow them, ATM I haven't a better idea, sorry).
This could sound logic: a sort of hidden team who set for a ghost mission
Other questions & comments:> I was curious about the Banshee, the aerial weapon Archadians uses to get rid of Nazara's defenses...
It's a sort of unmanned helicopter or it's more similar to an orbiting cannon? Let's say I'm an Armored Core fan... so I imagined it as a sort of unmanned aerial vehicle supplied with multiple gatling guns and rocket launchers...
> The story flow is good in my opinion. I've read it till Kaelin enters the party and I actually thought "that is a really good plot".
I'd leave Kaelin introduction there. There are no general rules about a playable character entering a party. See FuSoYa in FF4: he appears only in the lunar dungeon, near the very end of the game.
Just let the player use them a little (two dungeons are a fair amount of playable time) - so don't bother introducing him so far.
It's a pretty good idea.
> You want to make Desolo's changes more easy to see from half-game, right? If I were you, I'd begin changing Desolo's personality from that point you wrote about in your .txt on. You can gradually change his dialogues to make them darker throughout the two final dungeons; this way, the player would think that he's becoming more violent only because Kaelin's presence is annoying him... and then... SURPRISE!
I suggest you put some hint here and there to make a smart player understand what is really happening. You know, some NPC dialogue, some sentence with a hidden meaning...
> The City of Fun (Karakest) reminded me good ol' Gold Saucer... in a different way. Setting that city as a place where hooded men secretly revere Mallus was a surprising idea. It seems the last city a group of fanatics would use as a place to gather together, so it's perfectly okay
More will come soon

I hope this could help,
Jens
This post has been edited by Jens of Zanicuud: Sep 22 2012, 03:59 AM