I think you are missing the bigger goal of balance in this game when you focus solely on DPS. Outside of DPS, what do utility does each path generally offer?
Swordie: Tanking via great self buffs and the ability to pull mobs together
Cleric: Healing and great party buffs
Archer: Some great self buffs, decent debuffs
Wizard: Great debuffs, great party buffs, decent pet power (free’s up caster to do other things while dps’ing), some healing (featherfoot), and the ability to pull mobs together.
Granted not every wiz build can take advantage of all of those possibilities, but every wiz has a chance to have whichever utility they fancy while also pursing decent DPS.
So its not a good comparison to only compare wiz to say, swordie. You have to compare both DPS & Utility. Such as; a petalista1 barbarian3 has mob pulling utility + aoe DPS. Well a pyromancer2 linker2 also has mob pulling utility + aoe DPS. These are similar enough in purpose that you could begin to compare and contrast the two.
Lastly on world bosses, Psyhic Pressure + Ice Wall + Isa Rune (300% ice dmg) + Frost Cloud or Necro/Summon pets might be the best world boss killing class combo.

I don’t know of anyone that would choose psycho c3 