People normally compare the Fighter and the Magic-User when discussing issues of game balance. In D&D, low level fighters tend to be more durable in battle as opposed to the frail mage who can only lob one or two spells before having to hide for the rest of the day. But once hitting the high levels, mages can sling uber-powerful spells while fighters, while still formidable, cannot match their versatility and power.
It may be argued that fighters can have magical items. But then, so can mages.
It may be argued that fighters tend to have a linear progression in their development, while mages have this curved progression -- really crappy for a while, but then a sudden spurt up the power level chart.
But really, all this talk about balance depends on the game you're playing, and the game you want to play.
Players in a campaign with once-a-month sessions will have a different set of goals and expectations from the game from a weekly session campaign. Some players accept the high-risk, high-gain approach of the mages, who bet that they can survive long enough to become powerful -- that's the metagame they choose to play, eschewing the fighter's more even progression. Other players, perhaps those who tend to start off at higher levels (having done the leveling up thing a lot in the past and having no wish to repeat that part of the game), may find it unfair because that part of the game is gone -- mages getting instant jumps in power without having to sacrifice and suffer those early levels.
And others feel that all progression from low level to high level should be balanced across all classes.
Which game do you want to play?