Dark Dragon
Explorer
I don't see a big problem about that fighter vs wizard thing. I'm DMing an epic campaign (PCs at level 24), the party has a paladin15/cleric (fighting with a holy avenger), a fighter4/cleric (fighting with a +3 bastard sword), two wizard guys and a druid.
Against foes with quite high SR (40 and more is not that difficult for epic challenges), it came down to the paladin and the cleric to smack the opponent and it was the wizard's and the druid's job to help the front line to survive and fight more effectively (bark skin, stone skin, haste, heal, brilliant aura, mind blank...are all nice spells) and, not to forget, to counter spells!
So, every character type has to play an important role to help the party to survive and proceed on its mission.
Against foes with quite high SR (40 and more is not that difficult for epic challenges), it came down to the paladin and the cleric to smack the opponent and it was the wizard's and the druid's job to help the front line to survive and fight more effectively (bark skin, stone skin, haste, heal, brilliant aura, mind blank...are all nice spells) and, not to forget, to counter spells!
So, every character type has to play an important role to help the party to survive and proceed on its mission.