Grandia (the original) was... (prepare for another essay from me, I think) far more epic. In size, feel, and scope. Even compared to what should have been more epic, Grandia 2's storyline. I won't spoil, but suffice to say, both games are "save the world" things, by the end of it. I don't consider a basic cliché of RPGs to be a spoiler. :p
Grandia 2's characters were flat, the story was a re-tread, and generally not as fun. The world, though. Now that was amazing. Some of the areas were pure art. I still had fun, 'cause, see, it's still Grandia. It's still miles ahead of most, but compared to the original, it's lacking.
Grandia starts off small, almost kiddish. This could have turned people off, but stick with it. Soon it starts moving. Soon after introducing Feena (<3 to the power of infinity), the real story begins, hitting the necessary points to be a fine drama; happiness, sadness, loneliness, exultation, so on. This is where two failed to appeal, the characters didn't inspire any feeling of compassion. Even though it was far more serious, which should have helped drag you into the drama, G2 dropped the ball.
Kasuga, that's what I meant by soulless. Grandia 2 felt more like they were just going through the motions. The motions themselves were still fun, and I did finish it. But I don't feel the same interest, and there was definately no feeling of "Damn, it's over? But I want to see more of the characters interacting."
Grandia is a very linear game. There's no denying that. More linear than most RPGs, even. Somehow, they made G2 even moreso. Removing (hypothetical) secrets and extra areas, and the like.
Both games graphics were amazing, for the time. Have you ever sat down and looked at Grandia 1? Notice the texturing work? That's some really great texturing work, for the platform. Very little clipping, solid engine, especially considering it was a port. (I, like most, played the PSX version. Sorry, I don't own a Saturn, nor do I understand Japanese.)