How was the PS2 remake? I noticed that it got fan translated a while back but never got around to checking it out.
It's fairly similar to the original game for the most part. They added some stuff to make up for some of the original's shortcomings. There's an option to disable the pipe overlays now which makes navigating easier. (the dungeons are still largely the same ludicrously convoluted mazes they were in the Genesis) There's now a suspend-option so you can save-and-quite in the middle of dungeons though if you get wiped it's still back to the nearest town until you get the visiphone. Benched allies now have the option of either receiving XP while you're out fighting or crafting unique equipment based on the number of battles you fight until you return home. (you can get some crazy good stuff this way that makes the game a lot more doable but it also requires a guide in order to get the right items and a lot of grinding trash mobs)
At first, party members (mostly Nei and Rudo/Rudger) occasionally comment when talking to NPCs, though this stops once you get the ability to swap party members in and out. The exceptions are a handful of conversations your party members have with some NPCs that are references to their text adventure games. There's a "talk" option just like in PS4, but again it stops actually involving conversations after the Biolab. Cutscenes now have slightly more text meaning there's slightly more context to the story.
There's no longer party-specific inventories. Everyone can use all items you're carrying. Extra items are now stored at your home. Melee attacks in battle now have a light, normal and heavy variation with the lighter ones being quicker (meaning they go before the monster turns more often) and the heavier ones doing more damage) You get experience bonuses at the end based on whether you were able to quickly destroy the opposition, but it's fairly shallow. You also have the ability to "guard" (similar to Mario RPG) by pressing the confirm button just before an enemy attack lands and reduce the damage and dodge chance. Each party member also has a "limit break" whose gauge is mostly charged by defending and that range from not worth using to practically gamebreaking. To offset this, enemies hit even harder than before and if you fail to make use of the equipment crafting and/or guard mechanic later on, you will get slaughtered.
There's also a well-known, but extremely obscure "easter egg" that allows you to finish the game with a full party assuming you jump through two billion hoops including having a clear save from the first game and then loading a clear save from the second game made with that first clear save.
For the most part, it's the same game with the same grindiness and tough-as-nails battles and dungeons, it just looks different and your options are slightly different.