FFXI, at least in its hayday, wasn't an example of balance being difficult. It was an example of developers not caring to balance anything.
How many years were dragoons underpowered? And not just by a small amount, but they had huge glaring problems that were easily fixed. Like the fact dragoon's 2 hour was to call they're Wyvern. That was always an underpowered and terribly idea, but it took them years to change it to something useful. The developers ignored the problem, but that one fix was an easy change that every dragoon in the world had been suggesting for ages.
Perfect balance is impossible, even with the bland stats and lack of customization we have now is unbalanced. DRKs have been underpowered for an entire expansion. Since perfect balance is impossible, I say we should have some fun and interesting choices to go along with that lack of perfect balance.