So I finally finished the game, what a great ride. To my mind, the "bad ending" - if it can even be considered one - is too short, but apart from that, I can't think of anything substantial to criticize. That won't stop me from my usual nitpicking, though.
Considering the optional bosses, they're all manageable - if the player uses everything at his/her disposal (buffs, debuffs, status condition infliction, status condition protection, monster type weaknesses etc.). If he/she doesn't, well, he/she will be in for a lot of pain.
Now for the nitpicking (potential bugs and suggestions), based on my playthrough notes, in no particular order:
The description of the spell "corrosion" (in item form) states that it lowers an enemy's HP by 5% each turn (the same amount as the spell Toxin), while the description of the learned spell "corrosion" claims to lower an enemy's HP by 8% each turn (which is also stated when having successfully used the spell on an enemy).
The spell descriptions for "mega death" differ slightly. While the item form says "Chance of killing a group of enemies", the spell form claims it "Kills a group of enemies", indicating a failsafe characteristic that doesn't exist. The same applies to the "normal" Death spell.
Concerning the Ring of the Seven's description, it must be "INT +75" instead of "INT -75".
It seems that a party member equipped with the Book of Lightning loses a small percentage of his/her MP (about 0,5%) per turn in case he/she attacks normally. I can't imagine this is how it's supposed to work.
Why can silenced enemies still cast "gravity" (is it a physical skill instead of a spell?), and why can't "gravity" be cured with "purification"?
The warp device on Diaboros can also be accessed from behind (it's the same thing I mentioned earlier related to that one staircase in the God's Eye tower). There are also some obstruction mapping errors in Diaboros, but you should have received a private message from me depicting them, Ephiam.
Diaboros again: Defeating the western warp and southern warp guardians spawns a treasure chest respectively, but I couldn't find a new treasure chest for defeating the eastern warp guardian (in case there's supposed to be one). Maybe these two treasure chests should have been there from the start. At least then I wouldn't have questioned my sanity.
I find it very disappointing that the Meadowmite optional bosses (at least, which happened to me, the mage) can run away. (Optional) boss fights should always be a matter of life or death.
The optional boss fight against Shadow of Faulmah was too easy due to her status condition susceptibility (confusion in particular).
It might just be my personal preference, but a level cap of 45 is too low, especially when a player who kills all enemies in all dungeons and all optional bosses reaches it before the end of the game. With an increased level cap, clever players could - if they feel the need - grind in the final dungeon by continually pressing the wrong switch(es) in the "four switches room".
Does it work as intended when a party member equipped with a Three King Statue (+100% status protection) and the Tower Shield (+20% ailment rate) can suffer from a status condition? To my understanding, +100% status protection should cancel out +20% ailment rate instead of leading combined to +80% status protection. Also, is it intended that the Three King Statue doesn't prevent "down", "gravity", "bleeding" and "burning"?
I don't understand why Celes' color curse spells only target one enemy, whereas the enemies' color curse spells with the same names target the whole party. It seems the enemies generally use stronger versions of spells the player's party has access to, which is particularly aggravating when it comes to the spell "crystal wall".
There shouldn't be any passages in cities that are only one tile wide, as such passages tend to get blocked by roaming NPCs. Especially "navigating" in Ziazu is troublesome because of that.
Since I mute the sound of most RPGs I play, I would've have preferred a text message instead of a jingle to indicate that the player has defeated every monster in a dungeon.
Enough nitpicking. Thanks for another great JRPG with a distinguished story, a finely tuned/balanced battle system and superb dungeon design.