Well in Chrono Cross you could select from different kind of party members who were balanced, better at magic, evasion, etc.
That's most likely how FFXIV is gonna be. Your class will determine the attributes.
Also in chrono cross there was no real levels but there definately was leveling up. The level was basically like the physical level in FFXIV except that you didn't have to beat a whole bunch but only one boss monster. Each character in the party could then raise his stats to a certain limit determined by the player level.
That would mean you have to beat the story to have the maximum level, not that you have to get maximum level to beat the story.
But you would still have to grind each class to raise your stats. That system works in a massive story game but not in FFXIV :P
You would need 49 bosses and long story parts for each xD