Decided to pull the Balrog a bit up cause hes massively overcosted for what he does.
The Balrog, Durin´s Bane: 450
F 10/3+
S 9
D 9
A 4
W 10
C 7
M *
W 10
F 0
Wargear: Powerfull hands in flames, its never consider unarmed.
Special Rules:
Resistant to Magic; Terror; Fearless
Ancient Evil.
Evil of an Ancient World * : Although forgotten from an era lost past, the Balrog its an ancient terror of immense power and destruction.
At the beginning of every movement phase, the Balrog roll a number of dice according to how many wounds the Balrog has left, for each roll of a 5+, the Balrog gain 1 point of Might. (this ability does not acumulate with previous Might points gained on previous turns, and thus the player must roll every turn to see how many he gain).
In addition, Fire Breath and attacks with effects that automatically cause death on this model regardless how many wounds it has, only cause D3 +1 wounds instead.
Flames of Udûn: At the begining of every turn before priority rolls are made, the Balrog can burst a flame, if he does so, he loses 1 wound and 1 Will point, however he gain +1 to the rolls of the Evil of an Ancient World Special rule.
Balrog´s Special attacks:
The Balrog may choose to use one the listed abilities per turn at the cost of 1 point of Might.
Flaming Sword: Calling forth from Shadow and Flame like a swordsman taking his sword out of the quiver, the Balrog pulls his flaming sword to strike a might blow into his foes turning them into a pile of ash.
In the Combat phase, the Balrog strikes with a single attack rather than his normal number of attacks, if the Balrog wins the duel and sucessfully wound an oponent, that attack deal D6+1 wounds rather than 1. In addition, if an unmodified 6 is rolled on the to wound roll, it inflicts 2D6+1 instead (the amount of wounds is rolled before using Fate points and similar effect abilities are used). (cannot be combined with brutal power attacks).
Fiery Lash: Summoning his flaming whip, the Balrog brandishes his lash in a flurry before striking his foes.
In the Movement phase or Shooting phase, Fiery Lash count as a throwing weapon with the range of 8" and Strength of 7. In addition, all models (friend and foe) suffer Strength 7 hit within 2" of the initial target.
Inferno: In a burst of explosive rage and fire, the Balrog bellows, knocking out all those nearby.
In the combat phase if the Balrog wins the duel rolls, do not strike normally, all enemy models that made part of that combat suffer a Set Ablaze special rule and are knocked to the ground in which does not count towards the extinguish the blaze. (models like mumak and Smaug still suffer a Set ablaze special rule). (cannot be combined with brutal power attacks).
Breaking the wards:
At the end of the movement phase, the Balrog can try to break the enemy spell or any magical effect upon itself. Roll a dice, if the result its equal or higher than the oponent casting value, the spell effect has been broken and no longer take effect on the Balrog. In addition, if the result doubles the casting roll value of the oponent, the enemy wizard suffers a Strength 9 hit due to the sheer magical pressure that has countered the spell.
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That´s the changes I would propose.