Looking at the FFXIII saga as a model of release (three full-fledged games). Each game will be the size of a FFXIII game is specifically stated. In other words full scale 30+ hour RPG, and they also say plot wise nothing is off the table in terms of changes. They clarify they aren't changing everything but Kitase, Nomura, and Nojima feel since they were involved with the original game that they have the liberty to add / change what they want while still making fans happy. They also state they want FFVII Remake to gave a much shorter development cycle than FFXV.
-Weapon types includes: swords, daggers, lances, firearms, shields, royal arms, spells, and something called "machines" which weren't revealed yet;
-One of the screenshots has Ignis with a spear;
-You can improve and forge weapons from materials you collect;
-The game have magic synthesis to create new spells;
-When you call a summon they won't always do the same thing. They are entities that exist in the world itself. So depending on the situation they will do different things. Examples given Titan sometimes will run up and melee hit an enemy, sometimes he will throw boulders at the enemy and its possible he will even give up and leave the battle. They will also act differently in a dungeon than they will in the overworld. Its a huge focus for the staff for Summons to feel exciting and a major event when they show up, not just some random monster that swoops in. They want a sense of awe with them;
-There will be a growth system where you can spend ability points on weapon skills, Noctis, the party, bonuses etc. ;
-Each party member has their own "special talent" that improves with use. One example given is Prompto will ask the crew to take pit stops with the car where everyone gets out, goes to a spot and he takes photographs. You can then share these photo's on social media. The more you do it the better his pictures will be. These are in the game for both character development and will have real consequences for the game. Prompto is photography, Noctis is fishing, Ignis is cooking, and Gladiolus is survival instincts;
-The trunk of the Regalia acts as party storage;
-You can make branching decisions. Similar to older FFs dialogue choices;
-Four quest types: for fun (mini games:fishing/chocobo race/JusMon5 etc.), main story, monster hunts and regional quests. Currently over 200 quests and they're working on more;
-GI has this to say, "FFXV isn't Witcher 3 or Dragon Age Inquisition in terms of your to-do list. That isn't necessarily bad because your quest log isn't bloated by insignificant or uninteresting tasks.....inspires a feeling similar to pre-PS2 Final Fantasies where there were huge overworld maps that made the setting seem authentic and enormous - even if you didn't find a quest every step.";
-GI says there's a instrumental version of this in the game:
https://www.youtube.com/watch?v=pO8kTRv4l3o;-Tabata: "We have no intention to create sequels out of this";
-Kingsglaive has existed from 2013;
Story related info (SPOILERS):