This is precisely the forum to put it in. Well done!
Having beaten the game already, I can safely say that I had mixed feelings about it. There are minor spoilers, but nothing story-related.
From the very beginning, you are kept guessing about whose side you're really on. Are you working for the forces of good, or are you really being manipulated by the villains? The story has many shocking twists and provides lots of "I didn't see that coming" moments. In that regard, the story was well done and I was pleased at the end of it.
As you travel to find Lloyd, you slowly meet the cast of the first game, which I was really psyched about. Most will join you for a dungeon and then leave; others stay with you for much longer. You can use them in battle, but they don't gain experience; their level is set from the time they join from the time they leave.
You also are not allowed to control them on screen; it must always be Emil or Marta. You're also not allowed to remove Emil and Marta both from your party.
I went through nearly the entire game before learning that you can control the first game's cast in battle by simply switching your controlled character in battle. However, you must do this switch in every battle, and it got boring fast, even when I was just checking out their Mystic Artes.
While I'm on the subject of Mystic Artes: Radiant Roar, Marta's Mystic Arte, is broken. It almost makes the game too easy. Once you gain the ability to use it, you should never lose any battle. It does anywhere from 8-13,000 damage to all enemies and heals your whole party for about 2,000 HP.
This makes the game's bosses insanely easy. Many of them have Mystic Artes of their own, and rather than killing you outright, it brings anything it hits (which is usually your entire party) down to 1, which can be completely nullified by Radiant Roar. By waiting until these mega-skills fire to use Radiant Roar, you are effectively invincible.
Speaking of Marta, I controlled her for the entire game rather than Emil, and it was incredibly annoying having to reset my shortcuts every time she left my party (it happens A LOT). Even if she only leaves for a brief moment (read as: less than five minutes), the second she comes back, all my shortcuts were gone. My base moves were the same (the moves I set to control stick + B), but my D-pad and Wiimote shortcuts were erased.
I was disappointed to learn that Emil, Marta, and Tenebrae (to an extent) were the game's only new characters. After watching the introduction, you would think that the characters shown join your party (I was ultra psyched about using the girl), but they're actually villains. LAME. After learning that the Symphonia 1 cast don't gain experience, I didn't even bother using them - my party for 95% of the game consisted of Emil, Marta, and the same two monsters.
One of the biggest things I didn't like were the voices. While Emil is voiced by my hero, Johnny Yong Bosch, Lloyd, Sheena to an extent, and especially Zelos sound way different. Once you hear Zelos, especially in battle, you'll wonder if he might prefer ripped dudes over voluptuous hunnies.
The ability to use monsters is a neat change, except for one thing - you can't control them, ever. You're welcome to use three monsters and either Emil or Marta, but if your human dies, it's game over. Some monsters have inherent skills that can resurrect you upon death, but it only works once and it happens so fast that you might miss it happening. There is a monster battling arena in Meltokio where you can pit your monsters against other monsters, but joke's on you - you can't control them there, either.
Once the old cast starts joining you, you'll rarely be without at least one, so you don't have to use two monsters. The humans are more reliable than the monsters, they can actually be controlled, and they also have end-of-battle skits with themselves, Emil, and Marta. Whenever a monster kills the final enemy, it simply does a pose. No skit, ever.
Since I went so long without using the Tales of Symphonia 1 cast, I don't really know much about them in battle, and what I do know I can't say without invoking some heavy spoilers. By the time I learned you could use them, I was so used to using Marta that I didn't want to use anyone else.
The villains of the game look kinda silly - they wear bird masks over their eyes and shout things like, "FOR THE LIBERATION OF SYLVARANT!"
I would share the #1 thing I hate about ToS 2, but I consider it a big spoiler, so I can't.
All in all, however, it was an enjoyable game. My gripes could be considered minor, but it's my honest opinion of what the game was like.