You where not even there and yet you complain
I'll be quite honest, I've long ago have not thought of the mage class. They are just not meant as a solo class, period. If they where a solo class, gravi wouldn't have made it most of its monsters with a mid to higher mdef. If you made a toh to have it ok for mages and priests you'd make it too easy for most. Unfortunately one can't accustom every class for every toh though I do try to include a demon/undead type for 1 round.
With this TOH I was trying to make things hard, plain and simple, I specifically chose several of the monsters because of their ability to mob you, hense for snipers to be dropped and peco men to tank it out. Unfortunately, nothing ever goes as planed but with every round there was at least a 75% success rate aside round 3 and 5, but the final boss is what it is a final boss. Its not meant for everyone to pass it and toh is not meant to be easy. Certain classes will never out beat others in pvm solo.