I was planning to do a detailed review on this when I finished the game a few weeks ago, but I've forgotten a lot of what I wanted to say. :( So I'm going somewhat more basic:
Locations: What an insanely beautiful game. I took a ton of screenshots while exploring and during cutscenes. I love seeing all of the maps at different times of day, and how it's actually reflected in cutscenes. I thought Satorl Marsh was gorgeous, and then I got to Eryth Sea. Shittttt.
Music: Every time I was like, "Damn, this song is definitely my favorite track," another one popped up that I liked even more. I think I preferred the night-time version of the majority of them. An incredible soundtrack.
Characters: I like everyone in the party. It's nuts. That rarely happens for me. Even big, dumb Reyn is lovable. Okay, Riki isn't my favorite, but he's not bad. MELIA IS BEST GIRL I LOVE HER. But I also love Fioraaaa. (I honestly just love that there are so many GOOD female characters with personalities and different strengths and backstories.) Melia was the only character apart from Shulk who I used regularly. Her attacks were fun!
Outfits: I am a huge sucker for customization, so I really, really loved that you could change your armor appearance without changing the actual armor. The combinations of parts from different sets were also really well done, because I built a ton of great outfits from different sets that blended seamlessly with each other.
Story: So much to love here. The struggle of each party member and their reasons for joining; every reveal about the Mechon or the Bionis and how the Homs are actually in the dark about a lot of things; the twists, the ending! Ahhh, man, just so good.
Battle: This isn't quiiite the type of battle system I would typically go for. I don't like MMOs (not that this is one) for a lot of reasons, but I honestly had a lot of fun with these battles, probably because the abilities on the action bar and the cool down feature are one of the few things I don't mind about MMOs. I feel like the controls are very fluid and easy to get the hang of. Some might not like the auto-attack, but you have the Monado abilities to consider, like using Shield if the enemy is gonna use a powerful attack, or Enchant if you're fighting mechon, because your party can't hit them otherwise. You're also moving around to use Arts that do more damage from the back or side, and paying attention to HP. You also want to focus on whether you've used Break on an enemy, to open it up to a Topple from someone in your party with an appropriate move, and then a Daze attack once they're toppled. You're also keeping an eye on the Party Gauge, so that you can use a chain attack when it's full. Shulk is simply auto-attacking at a set interval in between you doing all of this.
This might make it sound way more complex than it needs to be, but once you've got a handful of battles under your belt, it goes quite smoothly and it's really not difficult to manage. Point is, if you were also having to press A to do a normal attack, it WOULD get frustrating. I'm glad it's set up the way that it is.
Map: If you've seen my updates on XC2, you've seen that I HATE THE MINI MAP SO MUCH. Especially when the one in this game is SO GOOD. It's easy to maneuver, the icons are clear, the layers are an amazing feature, and navigating using it is a breeze. With all of the fast traveling that you do for quests, it's a must to have a functional map.
Collectopaedia: I love this! As you pick up collectibles from around whichever given area you're in, it's not technically auto-logged in your collection. You manually go into the collectopaedia and add each one into the slots provided for the area, as long as you still have it in your inventory. When you fill all of the slots in each row, you get goodies.
Quests: I did EVERY. SINGLE. QUEST. Minus one. I didn't do one of the Replica Monado quests at the very end because I didn't feel like it, haha. Some were a bit tedious, but for the most part, I was enjoying every minute that I played this game, and I didn't mind doing them all. And there are a SHITTON.
Quest indicators: Whether it's the monsters that you need to target for a quest, or an item that you need, you can set active quests or simply look for the markers when you expand the map. Some people might not want all of this readily available, but this game is enormous, the first main area alone is expansive, and I personally like that feature when there are like 50 quests available in the first few hours. I think they can be turned off in the settings, but I'm not positive.
My one, single complaint about this game is the section just before you go to the final dungeon(s). The majority of your experience in the game comes from completing quests, and, as I said, I did them all. This kept me on par or above standard-level enemies in every given area (meaning not including the occasional super-high level big bois walking around some areas). You reach a point of no return, and suddenly you have a new slew of quests, requiring you to kill monsters that are a good 10-15 levels higher than you. But the problem lies in the fact that there's an unaddressed aspect of the game in which you can't even hit enemies that are that many levels higher than you unless you boost the shit out of your agility through equipment (or otherwise). I had to look this up because I was willing to try fighting them to get the quests done, but found that attacks weren't landing.
My problem with this is that, as I said, most of the xp throughout the game came from quests. I never had to grind, ever. I don't mind grinding in JRPGs, but I never needed to in this one up to this point. Suddenly every quest requires that I be a much higher level via grinding or basically redo all of my equipment and do this agility garbage. This is NOT post-game content, which I could probably expect to be more tedious.
So, I dropped it down to casual mode for this small part of the game. I was able to fight all of those monsters while I was a lower level. This made them like boss fights, so they were more challenging and took longer than normal enemies, but I was able to whittle them down and actually hit them. I completed all of the quests, got my level up to those monsters, and then went into the final area with the difficulty back on normal.
That was just so frustrating for me, because it was a total departure from the way I'd been playing/leveling for over 100 hours at that point.
In short, I love the hell out of this game. An easy 5 stars. I finished at around 130 hours, including Future Connected, which, being Melia-centric, was great story-wise, but not as enjoyable to play. It felt pretty tedious and something about the battles felt off/different because I kept getting my ass kicked.
Note: I have this on the Wii, as I got it for like $80 years back, but I never finished it. I was in Makna, so not super far. I'd wanted to come back to it for a long time, and ended up waiting on the DE. I'm so glad that I did.
Also, I've been playing XC2 since I finished this, and while I like a lot about it, it's not as good to me. The combat is insanely slow and I don't enjoy it most of the time because of that.