The pregen cleric of Moradin is only one point less strong than the pregen fighter, and has a better AC to boot -- the fighter has the same AC as the rogue! The fighter does do more damage at 1st level ... but that gap closes fast if the cleric casts crusader's strike (+1d6 damage for an hour) or spiritual hammer (extra attack for 1d8 for the next 10 turns, and can even be used at range).
So at 3rd level the fighter can kill four weak monsters, if they're all within melee range, twice a day. How many can the wizard take out with sleep or burning hands?
And I simply don't agree that being able to come up with outside-the-rules stunts in any way makes up for the fighter's marked lack of abilities. Any character, regardless of class, can do that.