Flying classes were actually useful. Level design was excellent on every map, whereas in the sequel there were quite a few mediocre ones. Some of the maps here are my favorites, and they never got ported into the sequel. There was aircraft in land battles, and you could switch to the cockpit view. Even the graphics were somewhat better because they had lighting and blur effects that were removed in the second game for some reason. Although, of course the models and textures are better in the second game, but that's to be expected. Still, I would say the original looked better for the year it came out in.

The sequel had more content, sure, a better campaign mode, better Galactic Conquest, space battles, and the ability to play as the Jedi. But the core gameplay actually suffered. The last class became locked, which meant fewer strategic options at the beginning of the battle (the most crucial time), and the new class (also locked) wasn't really so good that unlocking it felt rewarding. I found myself switching between classes way more in the original than in the sequel where I usually just stick to the first one (especially now that grenades stick, so it's easier to take out vehicles without a rocket launcher). And playing as the Jedi is not very fun after the novelty effect passes, especially when confronting other Jedi.

At the end of the day, the original does fewer things, but is close to perfection at them, whereas the sequel has more, but is somewhat flawed. I still come back to the first game every now and then to replay my favorite maps with my favorite classes, because there are experiences that the sequel just cannot replicate.