I've played a bit. I haven't played the original in ten years (never played the DeJap patch, only in Japanese with the old Ian Kelley FAQs), but it's pretty much exactly what I wanted after playing SO2 nine years ago-- SO1 remade just reusing SO2's engine. Yes, it plays and feels EXACTLY like the same game as SO2, just modded into SO1.
The voice acting isn't amazing, but it's fairly decent. It's a huuuuge improvement over SO2's (lol), at any rate. Some lines have some really odd delivery though.
There are a few enhancements to the battle system (vs. SO2 PS1) I've noticed:
1) Can do a three-hit combo with regular attacks before needing to recover for the next attack (at least with Roddick/Ratix, dunno about anyone else). Can't link to special attacks like Tales though.

2) Targeting button in Semi-Auto control mode. Semi-Auto in SO2 PSX made you confirm your target every single time you attack, doubling the number of button presses. Targeting button lets you select the enemy you want to attack, and it locks to that enemy, so no need to reconfirm your target. As an added plus, the battle now pauses when selecting targets, like it does in Tales.
3) Pressing the targeting button while running toward/chasing an enemy will cancel the attack! I'm sure the people who hated chasing those spinning witches in SO2 will really like this.
Stuff I'm iffy on-
1) The number one thing that still makes this battle system feel incredibly antiquated is still intact--The SLOOWWWW battle speed. They really should have sped it up. I need bunny shoes or something.
2) Real world map. The developers stated in an interview years ago that they wanted to implement a normal world map in SO1 but weren't able to for whatever reason. So they just used the "dungeon map" engine to handle it. But actually, I think the "dungeon map" engine was better... it was so much more intricately detailed. This just uses the same generic, uninteresting world map used in SO2. Towns are just a hop, skip, and a jump apart. I'd also say that the open world map doesn't really work all that well with SO1's world map, either. There are only three continents, two very small ones and one huge one. No islands or anything.
3) The new character designs. They're so simple and generic looking. I'm slowly getting used to them, but I still don't really understand the reason why they made all the Fellpool people look less like cat people and more like humans with tails and elf ears. One thing that sort of bothers me is that Millie's sprite looks an edit of Rena's; the head looks exactly the same, except with a different hair style.