As far as 1.0 is concerned, it had:
- Greater graphical fidelity, which meant higher textures and detail on a macro scale. (Please stop confusing graphics with aesthetics)
- It had an advanced lighting system, which allowed for a greater range of shadow "depth." (Unfortunately, it did not have the ability to produce environmental shadows of the quality we see in 2.0)
- Character aesthetics and detail were EXTREMELY high, so that even with very few character creation options to choose from, each character looked unique even at a distance.
- Environmental elements were copied and pasted to make up about 50% of the game's visible terrain. However, there were many iconic locations hidden throughout the game which were unique in both location and appearance.
- Character Inertia, where we didn't come to a stop the second we let go of the "w" key or analog stick. This added a lot of believable realism to characters.
- Cut-scenes with outstanding camera work/positioning, and effects. If the sun was just rising in the field where your cut-scene was activated, it would be rising in the cut-scene as well.
- 2.0's lighting effects are not unique to it's version. 1.0 had these same lighting effects moving forward with the patch that introduced Castrum Novum to the game. They were, however, only implemented to areas newly introduced to the game, which pretty much meant only Castrum Novum.
- Little known fact, the original release date for FFXIV 1.0 was projected as October 2013. For whatever reason, it was forced out early and incomplete, as a result we now have 2.0.
I found the game to have a much larger appeal to me in it's appearance as far as character design, lighting, and texture quality goes. Terrain design and placement does not equal graphics, this is aesthetics.
The voice acting in 2.0 does not suck, the audio quality does. In 1.0, the sound system was extremely well done and took advantage of everything your sound card was capable of producing. 2.0's sound system is... lacking. I frequently cringe when I hear spoken lines in the current version because half the time they fizzle at a particular octave.
1.0 as many "Legacy" players are recalling it, is not 1.0 but more likely 1.17 and onwards as around that patch the game picked up in quality extremely quickly.
The combat did suck for 1.0... it absolutely kicked ass at 1.19 which was a hybrid system of what we currently have and 1.23's system! (You could still cast spells while running, auto attack was just introduced, you didn't have to wait for auto attack because you still had all your regular "normal" attacks.
The UI sucked because it was laggy as hell all the way to 1.17. It was improved to beyond recognition by 1.19 and the lag was 99% gone (It still existed slightly while trying to sell junk to NPCs).
This is getting a bit long so I'll just say this.
Those of us dissatisfied with 2.0 only have ourselves to blame.
It was asked of us during the middle of 1.0's improvements:
Fix the game and improve upon the current system?
or
Drastic changes to all systems?
I think that, had we known what they meant by "drastic changes," we might have voted differently and 2.0, as we know it now, would not have existed.
*EDIT*
Honestly, all I really wanted for 1.0 (Legacy* 1.0, not actual 1.0) was for them to fix the server infrastructure (to combat the "plumes" problem) and give us richer environments.
We got richer environments... we're still waiting on the better servers apparently.